Hearthpwn

I prefer to read this as:

"Because yours are definitely the last 2 cards in your deck against this Odd Paladin, here's a Spreading Plague xoxoxox"

 - Jellyboi

This card give me tentaculat (ufo:tftd) flashback

EXTREMELY useful in Even Shaman, especially in Wild. Everyfin is Awesome and Bloodlust are the two best picks. My advice: Bloodlust for final burst, Everyfin for a beefier, more threatening board.

Insane card for arena. 

A weaker Ethereal Conjurer with built in high roll, nice.

For whatever reason, I believe in this card. Maybe I'm just a sucker for cards that give you more cards, but this card will find a pretty okay purpose in a deck at some point. 

Could be used to get a Bloodlust in Even Shaman... maybe???

60% chance to get Bloodlust if my math is right. Seems useful in even shaman.

I feel like this will be super busted in even Shaman. You fill your board pretty easily and you get to discover Bloodlust or The Storm Bringer which are both amazing (and that you can't normally run because they are odd cost).

Add to that the Menacing Nimbus that gives you a target for Earthen Might and I can see that deck getting a nice bump in power level.. Not sure if it will be enough in Standard, but it should in Wild.

Great, another way for Druid to get extra copies of OP spells.

How am I supposed to deal with 4 Webweaves?!

I was a bit hyped because it curves so well into Psychic Scream till i looked into priest's pool.

There are some classes with just a few high cost spells, I think might be useful in those, because discover almost guarantees a good card in those... Like in Warlock you are guaranteed to get Twisting Nether or Siphon Soul or both as a choice and pick whichever works better.

IMO, this card isn't as bad as most people vote it to be. Sure it might only see fringe play in budget decks and maybe some competitive decks due to its abysmal stats, but it's Battlecry is much better than most people might make it out to be. Including the cards revealed so far, 7 out of 9 classes will rarely ever have bad outcomes. Do bear in mind that this is a discover, so a class just needs at least half of the cards to be at least decent in order to have no bad outcomes most of the times.

Edit: Will not be including Wild Cards. There're just so many. TL;DR, worse in Wild for some classes, better in Wild for others.

Druid

Force of Nature - Decent

Living Mana - Decent

Nourish - Good

Starfall- Good

Webweave - Below Average

Spreading Plague - Good/Very Good (Depends)

Starfire - Good

Ultimate Infestation - Decent/Very Good (Depends)

Hunter

Explosive Shot - Decent

Lesser Emerald Spellstone - Good

To My Side! - Situational

Crushing Walls - Decent

Mage

Deck of Wonders - Below Average

Dragon's Fury - Situational

Blizzard - Very Good

Meteor - Very Good

Glacial Mysteries - Situational (Mostly Bad)

Pyroblast - Good

Paladin

Blessed Champion - Below Average

Call to Arms - Below Average

Holy Wrath - Below Average

Level Up! - Situational (Mostly Bad)

Shrink Ray - Decent

Avenging Wrath - Good

Spikeridged Steed - Very Good

Kangor's Endless Army - Situational

Dinosize - Decent

Lay on Hands - Good

Priest

Devour Mind - Decent

Holy Water - Situational

Power Word: Replicate - Decent

Embrace Darkness - Decent

Holy Fire - Good

Shadow Essence - Situational

Lesser Diamond Spellstone - Below Average

Psychic Scream - Very Good

Free From Amber - Good

Zerek's Cloning Gallery - Good

Mind Control - Good

Rogue

Assassinate - Decent

Myra's Unstable Element - Situational (Mostly Bad)

Necrium Vial - Probably Bad

Lesser Onyx Spellstone - Situational (Mostly Bad)

Vanish - Decent

Sprint - Good

Shaman

Bloodlust - Good

Volcano - Very Good

Eureka! - Situational (Probably Mostly Bad)

Lesser Sapphire Spellstone - Situational

Warlock

Bane of Doom - Decent

Feeding Time - Decent

Siphon Soul - Good

Twisting Nether - Very Good

Warrior

Brawl - Excellent

Sudden Genesis - Situational (Mostly Bad)

Deadly Arsenal - Bad (Still waiting for the game-breaking weapon to make this card viable)

Gather Your Party - Situational

Unidentified Shield - Good

Lesser Mithril Spellstone - Decent

The Boomship - Very Good

It's worth comparing this to Ethereal Conjuror - it was 5 cost, 6/3, discover a spell. So is one extra mana worth the worse stats and only getting a 5+ cost spell?

Maybe in Big Mage?

Not sure if it's worth a deckslot tho.

The idea behind the card is fine but stats are simply bad for 6. The art in gold going to be amazing though!

Arena card pretty much just for the added value of the battlecry. The stats are not ideal though even taking that battlecry into consideration. You would more likely see this as a 5 mana minion, but it is set to 6.

Will be really good in classes that don't have a ton of high cost spells. Warrior for example has Brawl, The Boomship, Lesser Mithril Spellstone, Unidentified Shield, Sudden Genesis, Deadly Arsenal, and Gather Your Party. The odds of only pulling three terrible cards out of that pool is pretty low.