I predict that the sleeper card of this set (that people only right off has an arena card) will be Vicious Fledgling. This card must be remove immediately otherwise it will snowball out of control (moreover if you can pick windfury) . Might see play in Beast Druid and Hunter.
I completely overlooked that one. Didn't realize it'd be another adapt every time it attacks; that is sick if you land a windfury first. And it's a three mana, so Hunter can really beef it up on curve with a turn 4 Houndmaster if it sticks.
Wow! I didn't notice this card on final reveal. And yes this card is sick, astounding and spectacular!
I predict that the sleeper card of this set (that people only right off has an arena card) will be Vicious Fledgling. This card must be remove immediately otherwise it will snowball out of control (moreover if you can pick windfury) . Might see play in Beast Druid and Hunter.
I completely overlooked that one. Didn't realize it'd be another adapt every time it attacks; that is sick if you land a windfury first. And it's a three mana, so Hunter can really beef it up on curve with a turn 4 Houndmaster if it sticks.
Wow! I didn't notice this card on final reveal. And yes this card is sick, astounding and spectacular!
I have my doubts on this one. It falls into the raging worgen category for me. It's threat, to be sure, and needs to be dealt with, it's just isn't that hard to do so. Not to mention you could just get shitty adapt options. Potential to be very dangerous does not in fact mean it will be. I do see this as being a rather good pick up in arena though.
Vicious Fledgling is bad in the same way that most 3 mana 3/3's are bad. Yes if it spirals out of control it'll end up good...but it'll happen so rarely (and often just die to a 2 mana card) that it's simply not worth the risk/spot in your deck.
As a rogue player, I think Bittertide Hydra is great. By all means, play your 5 mana kill yourself card. It allows me to focus on a single target and you lose 30% of your health in the process. Have fun! Backstab, Si, Eviscerate.
You've just burned 3 cards to deal with one and in the process dealt a grand total of 9 damage to the opposition hero (you'd have dealt 6 anyway just using the cards). Hell your backstab in this situation is basically a 0 mana Sinister Strike. Not to mention you've just burned two spells that you were potentially going to combo with Auctioneer.
Bittertide will be good like Fel Reaver was because people get stars in their eyes and think they have to abuse the hell out of the mechanic by making insanely low value plays. Will it sometimes cost you games? Sure, but it'll win you them more often.
Vicious Fledgling is bad in the same way that most 3 mana 3/3's are bad. Yes if it spirals out of control it'll end up good...but it'll happen so rarely (and often just die to a 2 mana card) that it's simply not worth the risk/spot in your deck.
I see the card as a "must kill" target. And one of the better 3 mana cards to pick in arena (I'm mostly an arena player). A 3 mana 3/3 stealth or 3 mana 3/3 divine shield is a decent/good card. Only a taunt /silence will prevent this card from building up and wind fury gives double the chance of getting a good pick.
this card either needs stealth or shield on its first turn or windfury into one of them. Windfury->stealth next turn gets shield -> poison would be one of the best scenarios (although random). Then just continue with shield/stealth and stat boosts. I could see situations where this does be just a normal 3/3 (going second, no 2 drop, taunt block, etc) but others where it can get ugly.
I wanted to answer before I read every one else's answers. In no particular order:
OVERHYPED -Jungle Giants/Barnabus the Stomper - I think it's less impactful than people theorize. That doesn't mean I think it's bad. Ramp Druid is almost always viable in some form or another. I just don't think it's the end-all-be-all that some predict.
-Dinomancy - I just don't think a hunter will exist where you'd rather make the investment you need to for this to pay off. The turn you play it is at least like a 5 mana investment (minion on board, this card, HP). That is SLOWWWW. Again, I don't think it's bad, and I recognize the snowball potential. But I think people will generally agree that it may just be better to use the card slot on something else.
- The Last Kaleidosaur - I'll just say it. I think this is unplayable in a competitive standard environment.
UNDERHYPED Disclaimer: I'm not saying these cards are awesome. I am just saying they are better than the lack of chatter they've received.
Primalfin Totem - I think this card is why the Murloc shaman will work. It needed one more multi summon card and it got it. Now, I'm not sure if that deck is good enough. But I don't think it's a joke anymore because of a card like this. I think the fact that it's 2 mana is also really important. Just think of the times where you had difficulty dealing with at 3 mana mana tide on turn 3.
Tidal Surge - I think Control Shaman may be the best or second best control deck of this meta game and this card Is a big reason why. Removal and Heal at a cheap mana cost. What else could control want?
Primordial Drake - now play the curator in everything! No seriously, you can probably play curator in every midrange deck now.
I tried theorycrafting a Druid Quest deck and I have to agree, I don't think it will be better than Jade Druid, a big reason is because we are missing Rag and Sylvanas, but playing 0 mana Y'Shaarj, Ysera, Soggoth, AoW and Bog Creeper still sounds pretty tempting so if I get Jungle Giants from a pack I'll probably try something like this:
I've tried to take care of the need for card draw to really benefit of all your minions costing 0 by including 2x Nourish, Elise the Trailblazer, Hemet, Jungle Hunter and a Fight Promoter. Hemet will make your topdecks better while also having 5+ atk for the quest, Elise as well help you complete the quest and she can give you a way to refill your hand once you've activated the quest and played out all your minions...I might wanna try to find room for a 2nd Fight Promoter depending on how well she performs.
The Curator seems to be a better option than Fight Promoter - ideally, it pulls Alexstrasza and Tyrantus, and you win the game the following turn. Bright-Eyed Scout is also an option - if she pulls a big minion on turn four, you might not have to complete the quest in order to win the game. Having an alternate win-condition will be important for the non-aggro quests - presumably, there will be plenty of games where Druid simply whiffs on completing the quest, but a lucky Scout might save the day.
I considered Bright-Eyed Scout, but didn't wanna include it due to being a 3 attack minion and I want to fulfill the quest as quickly as possible so I feel it might be better running like Shellshifter instead, I may be wrong, maybe I could swap those if Shellshifter turns out to be too crap....however remember that Bright-Eyed Scout will also make your 0 mana minions cost 5 if you play this after Barnabus the Stomper so it kinda has anti-synergy with the quest.
If you want to watch a few videos on Ramp Druid, I'd recommend watching Day[9]'s YT channel - search for his recent Heroic Tavern Brawl run with the deck. He went 6-3. Barnabus the Stomper isn't a traditional Ramp Druid deck - it runs some cheap minions - but nevertheless, there are important similarities between the decks. I think you might be able to drop Swipe and Wrath - you trust your deck to put big taunts into play quickly, and they act as your removal. Elise the Trailblazer and Celestial Dreamer also seem a little weak - you want to end the game quickly once you complete the quest by playing lots of big dudes, so the game will rarely last long enough to draw the Un'Goro pack. More often than not, they'll both be vanilla 5/5s. There aren't a lot of cheap options in Standard - Lotus Agents might be something to consider, I suppose. Ancient of Lore hasn't seen play since the nerf - but it draws a free minion once the quest pops, so it also looks like something to consider.
Vicious Fledgling is bad in the same way that most 3 mana 3/3's are bad. Yes if it spirals out of control it'll end up good...but it'll happen so rarely (and often just die to a 2 mana card) that it's simply not worth the risk/spot in your deck.
I see the card as a "must kill" target. And one of the better 3 mana cards to pick in arena (I'm mostly an arena player). A 3 mana 3/3 stealth or 3 mana 3/3 divine shield is a decent/good card. Only a taunt /silence will prevent this card from building up and wind fury gives double the chance of getting a good pick.
this card either needs stealth or shield on its first turn or windfury into one of them. Windfury->stealth next turn gets shield -> poison would be one of the best scenarios (although random). Then just continue with shield/stealth and stat boosts. I could see situations where this does be just a normal 3/3 (going second, no 2 drop, taunt block, etc) but others where it can get ugly.
I'm coming at this from an arena perspective too - as somebody who pretty much only plays Arena these days. I think it's below average. I mean it's better than many other 3 mana 3/3's but...these days a 3 mana 3/3 just isn't good enough in a world of Hired Guns etc.
Yeah it can be really good, but I don't see it surviving the turn and then hitting face into the right adaptation enough to justify it. I'd pick it over an MCT, I wouldn't pick it over any 3/4 or 4/3. Best of a bad bunch basically.
Overhyped: Elise the Trailblazer- This card is only really powerful in a meta where games go to fatigue on a semi regular basis. Jades plus the quests ensure that that will never occur.
Bloodbloom: Even though this card sacrifices health which Warlock has trouble regaining, the massive tempo swing this card creates will almost always be worth it. I expect his card along with Violet Illusionist to be played in pretty much every slow Warlock list.
Stubborn Gastropod: For 2 mana you get a minion with infinite attack, taunt and the beast tag. I see this being played often in more aggressive hunter variants as an incredibly efficient method of getting through all the new taunt cards as well as protecting their board from minion trades. This might even see play in pirate warrior and zoo for the same purpose.
Alright time for a massive textwall, I'll do neutrals first:
Overrated:
Servant of Kalimos: Don't get me wrong, this card is super strong and belongs in every Elemental deck, but people are rating it highly for the wrong reasons. It's not a curvestone card, as a 5 mana 4/5 that doesn't affect the board is not something you're happy with and will either put you behind or open you up to aggression. It's value lies in playing it, say, turn 8 following Blazecaller to re-fuel.
Gluttonous Ooze: Again good card, but people are overreacting about it's value. Just like how it's good tech against certain metas, the metas can adapt around it. Pirates dropping Arcanite Reaver, Control Wars dropping Gorehowl etc, leaves this thing only gaining 3 Armor while breaking 3 attack weapons with 1 charge left. For the 1 extra mana up from Acidic Swamp Ooze, you got 1 health on the minion and 3 health, that's not even that much better and it's much more difficult to weave into a turn than a 2 cost play.
Spiritsinger Umbra: This has the potential to open up new archetypes and become a staple in some decks, but people calling this the most powerful card of the expansion are overreacting. Unlike Brann which you're comfortable playing on curve, a 4 mana 3/4 is not something you're happy about and is super easy to remove if played on curve. If you try to combo it at a later turn, it'll most likely be a low impact Deathrattle like Loot Hoarder or Kindly Grandmother than a Highmane or Cairne. 6 mana 4/3+2/1+draw a card, 6 mana 4/3+1/1+3/2. That's good but not meta defining. Moreover, Deathrattles in Hearthstone are on average weaker than Battlecries, usually just spawning tokens, and the most dominant Deathrattle effect in the game is rotating out. It's very slow and much more difficult to build a deck around it than people think.
Underrated
Fire Fly: It's a low impact card, but it's potential implications on the meta is huge. I actually thought it was unimpressive when it was first released, but now knowing all the cards that have been revealed, I've changed my mind. Being able to trigger elemental effects on demand is excellent utility already, but more importantly it helps open up new archetypes such as Quest Rogue which will likely depend on this and Igneous Elemental. Overall the card's floor is "2 mana summon 2 1/2s" which isn't actually that bad stats wise, and it trades pretty nicely into the 1 mana 2/1s that will likely infest the meta, as well as tokens pirates etc early on.
Rockpool Hunter: I don't think people appreciate just how dirty this card is. Murlocs are supposed to be understatted due to the potential synergy with cards like Warleader. This thing straight up has vanilla stats with upside. Being able to buff a Warleader or Finja out of removal range is insane utility. The only issue is that the most likely Murloc deck, Shaman, might opt to run a low number of 1 drops and prioritize the quest, but worse comes to worse you just plop this guy down as a 2 mana 2/3 and buff it with Warleader next turn. It's also a much stickier 2 drop than your Murloc Tidehunters etc, and is more likely to keep a body up to trigger Primalfin Lookout. This is sleeper OP and I would not be surprised if we get calls for nerfs.
Fire Plume Phoenix: A 4 mana 3/3 deal 2 damage is basically a weaker SI:7 Agent which often times you have to "play for 4 mana" due to lack of Coin or Backstab anyway. It's not broken, but any card that develops a body while removing something is always positive tempo and should always be considered for a deck. At the very least, it'll be a power pick in Arena. More importantly though this is an important curve card for Elemental Shaman which lacks Water Elemental etc in the 4 slot.
Vicious Fledgling: I used to think it was just a 3 mana 3/3 with upside, but after listening to some streamers like Noxious, I think this card is sleeper OP. It could be too slow, but it could effectively be a 1 card win condition for the right kind of deck, for example a Paladin can plop a divine shield onto this thing. If you can trigger Stealth or Windfury on the first attack, then you can Adapt again for a nice divine shield or spell immunity or health boost for survivability, then again, and again, and again...
The Marsh Queen: People are overreacting with the "ZOMG Hunter SMORC meta" responses. This card is super difficult to deckbuild around. You want to run a high 1 drop count to consistently complete the quest, but you also don't want so many that you dilute your topdecks late game. This is very problematic late game. Ideally you get a draw train with your Raptors and flood the board every game, but realistically you'll still have around 15 cards left in your deck by the time you complete the quest, meaning that you actually only have around a 50% chance of drawing a Raptor at the start of each turn. If you topdeck a few of your low impact 1 drops, you're going to run out of fuel and get turned on by the opponent. Conversely, if you start filling your deck with things like Savannah Highmane, you're unlikely to complete the quest and effectively play the entire game down a card. Moreover, in a 1 drop spam deck, your build will likely be very aggressive in nature. Wasting turn 1 on a "do nothing" play could be cripping in an Aggro matchup.
Mana Bind: This card is just abysmal and it's only hope of seeing any play is in Open the Waygate decks as a spell generator. People play around it the same way as they'd play around Counterspell and more often than not you'll get garbage like a coin. It's significantly worse than Counterspell (which doesn't see much play as is) though because it doesn't disrupt the opponent's play. In a situation where your opponent is willing to play a high value 5+ cost spell into your secret. They're likely pushing for game. This does nothing to prevent your opponent from going off on that big swing turn, and even a 0 mana copy of the same spell might not get you out of the situation.
Pyros: Yes there's a lot of value printed on this card, but to take advantage of that value, you're playing a 2 mana 2/2, a 6 mana 6/6, and a 10 mana 10/10. In Elementals which wants to play curvestone, all 3 of those are terrible and will put you behind. The only place for this card IMO is if a N'Zoth Mage or something ends up working.
Corrupting Mist: So many people saying it's a better Doomsayer. I think it's a significantly worse Doomsayer. Doomsayer was powerful because if it stayed on board, it ensures you the initiative. Corrupting Mist lets your opponent keep the initiative which is just awful. They have no reason to not continue developing their board and can just let the Corrupted minions die. Sure you can develop your own board after playing Corrupting Mist, but what your opponent is going to do is just trade their Corrupted Minions into your healthy minions, then set up a better board than you because they had 2 extra mana to work with. It might still find it's way into a deck alongside Doomsayer for a "handlock", but I wouldn't be surprised if it sees exactly 0 competitive play.
Underrated:
Primordial Glyph: This card is basically universally agreed upon as strong and I still think it's underrated. It is so stupid it's not even funny. Not only do you not pay any extra mana overall, it will often be played as a curve filler on a turn where you had extra mana, and produce a high impact spell that you can more easily weave into a later turn due to the reduced cost. This card would be playable even if it generated a random spell, but the huge flexibility granted by Discover is just icing on the cake.
Radiant Elemental: The best comparison is Sorcerer's Apprentice, but I believe it's even better due to how easily Priest can keep this thing alive. Heck it allows you to cast Power Word Shield on it for free. This could potentially open up some degenerate combos for Priest. Potential interaction with Lyra the Sunshard is interesting as well, though Lyra has a stats issue.
Shadow Visions: Being able to tutor out a card from your deck is just insane. It effectively doubles your chances of hitting every key spell in your deck. Need hard removal? Go get SWD. Need a board clear? Go get Dragonfire Potion. The flexibility that this card enables for a Priest deck is excellent. As a non-curvestone deck with tons of late game sustain via it's hero power, it's more comfortable "wasting" mana on a card like this to get exactly what you need.
Razorpetal Lasher: This is very similar to Tomb Pillager in that it generates a card to fuel your Miracle turns. Obviously Pillager is much better due to the superior stat distribution and coin allowing you to weave in more spells, but anytime you're adding cheap spells to Rogue, while not being a significant drain tempo wise, it's a win. Compare this with Undercity Huckster which while a higher ceiling has the potential to get you a useless card. This will always give you fuel.
Not exactly an Ungoro card but i believe Dirty Rat will be one of the best cards especially if Open the Waygate will be in the meta as it absolutely destroys combo decks and makes your win condition worthless, the same of course can be said for many of the other quests.
Another card that will be in almost every shaman deck is Devolve, it is soo powerful in destroying quest rewards and in general a lot of cards seem to really get punished by it.
A ungoro card im really looking up to is Bright-Eyed Scout it will be a card in every lategame control deck as you wont care too much about making your cheap cards a bit more expensive, but if this lands on a Ysera or Tyrantus on turn 4 you might have won the game just by that.
Also Sunkeeper Tarim will be a very strong paladin card, i doubt it pushes paladin into viablity but its a really strong card by itself. the fact that it has taunt and costs 1 less makes it better than eadric especially against aggressive decks, its very good against jades too and lets you easily trade the board if you had silver hand recruits on board.
Death to all who oppose the Horde!
Vicious Fledgling is bad in the same way that most 3 mana 3/3's are bad. Yes if it spirals out of control it'll end up good...but it'll happen so rarely (and often just die to a 2 mana card) that it's simply not worth the risk/spot in your deck.
I wanted to answer before I read every one else's answers. In no particular order:
OVERHYPED
-Jungle Giants/Barnabus the Stomper - I think it's less impactful than people theorize. That doesn't mean I think it's bad. Ramp Druid is almost always viable in some form or another. I just don't think it's the end-all-be-all that some predict.
-Dinomancy - I just don't think a hunter will exist where you'd rather make the investment you need to for this to pay off. The turn you play it is at least like a 5 mana investment (minion on board, this card, HP). That is SLOWWWW. Again, I don't think it's bad, and I recognize the snowball potential. But I think people will generally agree that it may just be better to use the card slot on something else.
- The Last Kaleidosaur - I'll just say it. I think this is unplayable in a competitive standard environment.
UNDERHYPED
Disclaimer: I'm not saying these cards are awesome. I am just saying they are better than the lack of chatter they've received.
Primalfin Totem - I think this card is why the Murloc shaman will work. It needed one more multi summon card and it got it. Now, I'm not sure if that deck is good enough. But I don't think it's a joke anymore because of a card like this. I think the fact that it's 2 mana is also really important. Just think of the times where you had difficulty dealing with at 3 mana mana tide on turn 3.
Tidal Surge - I think Control Shaman may be the best or second best control deck of this meta game and this card Is a big reason why. Removal and Heal at a cheap mana cost. What else could control want?
Primordial Drake - now play the curator in everything! No seriously, you can probably play curator in every midrange deck now.
I have an Underdog card: Hallucination this should see play in every rogue deck
I suspect the Tar Elementals are over-hyped all three of them.
And I suspect Thunder Lizards are a better choice than Stoneshaper because you can squeeze them in on 3 mana.
Overhyped: Elise the Trailblazer- This card is only really powerful in a meta where games go to fatigue on a semi regular basis. Jades plus the quests ensure that that will never occur.
Underhyped:
Alright time for a massive textwall, I'll do neutrals first:
Overrated:
Servant of Kalimos: Don't get me wrong, this card is super strong and belongs in every Elemental deck, but people are rating it highly for the wrong reasons. It's not a curvestone card, as a 5 mana 4/5 that doesn't affect the board is not something you're happy with and will either put you behind or open you up to aggression. It's value lies in playing it, say, turn 8 following Blazecaller to re-fuel.
Gluttonous Ooze: Again good card, but people are overreacting about it's value. Just like how it's good tech against certain metas, the metas can adapt around it. Pirates dropping Arcanite Reaver, Control Wars dropping Gorehowl etc, leaves this thing only gaining 3 Armor while breaking 3 attack weapons with 1 charge left. For the 1 extra mana up from Acidic Swamp Ooze, you got 1 health on the minion and 3 health, that's not even that much better and it's much more difficult to weave into a turn than a 2 cost play.
Spiritsinger Umbra: This has the potential to open up new archetypes and become a staple in some decks, but people calling this the most powerful card of the expansion are overreacting. Unlike Brann which you're comfortable playing on curve, a 4 mana 3/4 is not something you're happy about and is super easy to remove if played on curve. If you try to combo it at a later turn, it'll most likely be a low impact Deathrattle like Loot Hoarder or Kindly Grandmother than a Highmane or Cairne. 6 mana 4/3+2/1+draw a card, 6 mana 4/3+1/1+3/2. That's good but not meta defining. Moreover, Deathrattles in Hearthstone are on average weaker than Battlecries, usually just spawning tokens, and the most dominant Deathrattle effect in the game is rotating out. It's very slow and much more difficult to build a deck around it than people think.
Underrated
Fire Fly: It's a low impact card, but it's potential implications on the meta is huge. I actually thought it was unimpressive when it was first released, but now knowing all the cards that have been revealed, I've changed my mind. Being able to trigger elemental effects on demand is excellent utility already, but more importantly it helps open up new archetypes such as Quest Rogue which will likely depend on this and Igneous Elemental. Overall the card's floor is "2 mana summon 2 1/2s" which isn't actually that bad stats wise, and it trades pretty nicely into the 1 mana 2/1s that will likely infest the meta, as well as tokens pirates etc early on.
Rockpool Hunter: I don't think people appreciate just how dirty this card is. Murlocs are supposed to be understatted due to the potential synergy with cards like Warleader. This thing straight up has vanilla stats with upside. Being able to buff a Warleader or Finja out of removal range is insane utility. The only issue is that the most likely Murloc deck, Shaman, might opt to run a low number of 1 drops and prioritize the quest, but worse comes to worse you just plop this guy down as a 2 mana 2/3 and buff it with Warleader next turn. It's also a much stickier 2 drop than your Murloc Tidehunters etc, and is more likely to keep a body up to trigger Primalfin Lookout. This is sleeper OP and I would not be surprised if we get calls for nerfs.
Fire Plume Phoenix: A 4 mana 3/3 deal 2 damage is basically a weaker SI:7 Agent which often times you have to "play for 4 mana" due to lack of Coin or Backstab anyway. It's not broken, but any card that develops a body while removing something is always positive tempo and should always be considered for a deck. At the very least, it'll be a power pick in Arena. More importantly though this is an important curve card for Elemental Shaman which lacks Water Elemental etc in the 4 slot.
Vicious Fledgling: I used to think it was just a 3 mana 3/3 with upside, but after listening to some streamers like Noxious, I think this card is sleeper OP. It could be too slow, but it could effectively be a 1 card win condition for the right kind of deck, for example a Paladin can plop a divine shield onto this thing. If you can trigger Stealth or Windfury on the first attack, then you can Adapt again for a nice divine shield or spell immunity or health boost for survivability, then again, and again, and again...
Elise the Trailblazer: I'll just leave this here: http://www.hearthpwn.com/forums/hearthstone-general/card-discussion/188156-new-legendary-card-elise-the-trailblazer?comment=125
Now for Class Cards:
Overrated:
The Marsh Queen: People are overreacting with the "ZOMG Hunter SMORC meta" responses. This card is super difficult to deckbuild around. You want to run a high 1 drop count to consistently complete the quest, but you also don't want so many that you dilute your topdecks late game. This is very problematic late game. Ideally you get a draw train with your Raptors and flood the board every game, but realistically you'll still have around 15 cards left in your deck by the time you complete the quest, meaning that you actually only have around a 50% chance of drawing a Raptor at the start of each turn. If you topdeck a few of your low impact 1 drops, you're going to run out of fuel and get turned on by the opponent. Conversely, if you start filling your deck with things like Savannah Highmane, you're unlikely to complete the quest and effectively play the entire game down a card. Moreover, in a 1 drop spam deck, your build will likely be very aggressive in nature. Wasting turn 1 on a "do nothing" play could be cripping in an Aggro matchup.
Mana Bind: This card is just abysmal and it's only hope of seeing any play is in Open the Waygate decks as a spell generator. People play around it the same way as they'd play around Counterspell and more often than not you'll get garbage like a coin. It's significantly worse than Counterspell (which doesn't see much play as is) though because it doesn't disrupt the opponent's play. In a situation where your opponent is willing to play a high value 5+ cost spell into your secret. They're likely pushing for game. This does nothing to prevent your opponent from going off on that big swing turn, and even a 0 mana copy of the same spell might not get you out of the situation.
Pyros: Yes there's a lot of value printed on this card, but to take advantage of that value, you're playing a 2 mana 2/2, a 6 mana 6/6, and a 10 mana 10/10. In Elementals which wants to play curvestone, all 3 of those are terrible and will put you behind. The only place for this card IMO is if a N'Zoth Mage or something ends up working.
Corrupting Mist: So many people saying it's a better Doomsayer. I think it's a significantly worse Doomsayer. Doomsayer was powerful because if it stayed on board, it ensures you the initiative. Corrupting Mist lets your opponent keep the initiative which is just awful. They have no reason to not continue developing their board and can just let the Corrupted minions die. Sure you can develop your own board after playing Corrupting Mist, but what your opponent is going to do is just trade their Corrupted Minions into your healthy minions, then set up a better board than you because they had 2 extra mana to work with. It might still find it's way into a deck alongside Doomsayer for a "handlock", but I wouldn't be surprised if it sees exactly 0 competitive play.
Underrated:
Primordial Glyph: This card is basically universally agreed upon as strong and I still think it's underrated. It is so stupid it's not even funny. Not only do you not pay any extra mana overall, it will often be played as a curve filler on a turn where you had extra mana, and produce a high impact spell that you can more easily weave into a later turn due to the reduced cost. This card would be playable even if it generated a random spell, but the huge flexibility granted by Discover is just icing on the cake.
Radiant Elemental: The best comparison is Sorcerer's Apprentice, but I believe it's even better due to how easily Priest can keep this thing alive. Heck it allows you to cast Power Word Shield on it for free. This could potentially open up some degenerate combos for Priest. Potential interaction with Lyra the Sunshard is interesting as well, though Lyra has a stats issue.
Shadow Visions: Being able to tutor out a card from your deck is just insane. It effectively doubles your chances of hitting every key spell in your deck. Need hard removal? Go get SWD. Need a board clear? Go get Dragonfire Potion. The flexibility that this card enables for a Priest deck is excellent. As a non-curvestone deck with tons of late game sustain via it's hero power, it's more comfortable "wasting" mana on a card like this to get exactly what you need.
Razorpetal Lasher: This is very similar to Tomb Pillager in that it generates a card to fuel your Miracle turns. Obviously Pillager is much better due to the superior stat distribution and coin allowing you to weave in more spells, but anytime you're adding cheap spells to Rogue, while not being a significant drain tempo wise, it's a win. Compare this with Undercity Huckster which while a higher ceiling has the potential to get you a useless card. This will always give you fuel.
Sherazin, Corpse Flower: I've already discussed this in the main thread in depth. TLDR, the card could flop but has immense potential, you'd have to be braindead like Beyond"Shaku is bad"theVeil to not see that: http://www.hearthpwn.com/forums/hearthstone-general/card-discussion/188161-new-rogue-legendary-card-sherazin-corpse-flower?comment=124, http://www.hearthpwn.com/forums/hearthstone-general/card-discussion/188161-new-rogue-legendary-card-sherazin-corpse-flower?comment=182
Unite the Murlocs: With a potential stalwart card like Rockpool Hunter added to the Murloc pool, the deck is easier to trigger than ever and can more naturally curve out while protecting your key Murlocs. I've already discussed in depth here, and just because it can't be emphasized enough, this thing could potentially give you a 5 mana 8/8 +10 card advantage: http://www.hearthpwn.com/forums/hearthstone-general/card-discussion/188446-new-shaman-quest-unite-the-murlocs?comment=120
On the Vicious Fledgeling... If you manage to land Windfury on its first attack, does it get another attack on that same turn?
Not exactly an Ungoro card but i believe Dirty Rat will be one of the best cards especially if Open the Waygate will be in the meta as it absolutely destroys combo decks and makes your win condition worthless, the same of course can be said for many of the other quests.
Another card that will be in almost every shaman deck is Devolve, it is soo powerful in destroying quest rewards and in general a lot of cards seem to really get punished by it.
A ungoro card im really looking up to is Bright-Eyed Scout it will be a card in every lategame control deck as you wont care too much about making your cheap cards a bit more expensive, but if this lands on a Ysera or Tyrantus on turn 4 you might have won the game just by that.
Also Sunkeeper Tarim will be a very strong paladin card, i doubt it pushes paladin into viablity but its a really strong card by itself. the fact that it has taunt and costs 1 less makes it better than eadric especially against aggressive decks, its very good against jades too and lets you easily trade the board if you had silver hand recruits on board.
Envenom Weapon with Blade Flurry = mass poison.