Hearthpwn

I'm liking this card You don't even have to have it in hand. And it isn't like Echo is going to go away. More x-pac Means more room to grow. (thumbs up)

turn 5 you have two cheap shots and a 5/7? or realistically you would have a 5/4 - 5/3 left over. 
Seems like it could be good. But where does it fit in, if it does see play?

I can't wait to see the golden animation on this card. Seems like it would be amazing

Super threatening 4 drop that starts with competitive stats.

Looks pretty good to me.

It feels natural that Rogues would get Echo synergy cards like this, but in terms of value and ease of use, this card, like many similar cards before it, competes with Edwin VanCleef. 

A play with this card would involve it surviving a turn, then playing an Echo card a bunch to boost it, but relying on a minion surviving a turn has always been a dangerously optimistic play only suited for cards as strong as Vicious Fledgling, and I have a feeling this card is not one of them.

Well, the way I see it, the stats are okay enough that you can just drop it on turn 4 and pass. 

Its not like Questing Adventurer that you would never play naked. its more like Unbound Elemental where you can play it on T3 and if it goes unanswered, it can snowball. 

This is better, because its easier to play a lot of echo cards than overload cards (thats what echo is designed to do), and a 4/3/5 is typically better than a 3/2/4. 

consensus; if you drop it on T4 and they remove it, thats okay. You went 1 for 1 because its hard to find a minion that can kill this for free. If they don't, you can get great board control with cheap shot and snowball from there. 

Not saying this is good, its just not bad. And it plays a different role than edwin or questing.  

I feel obliged to do some comparison as a way of evaluating this card a bit more precise:

Secretkeeper - 1 mana, 1/2 - Really cheap card that saw play in Paladin the most. It is easy to remove, but it curves good with Paladin secrets which cost 1. This one could snowball very fast, feeds on opponents' secrets too and saw a fair share of play, especially in Secret Paladin which was T1 deck back in the day.

Math: It's over average stats for its cost after playing only one secret which can cost 1, 2 or 3, so naturally, it's best in Paladin, and worst in Mage, while Hunter and Rogue can buff it on curve, which is also nice.

Questing Adventurer - 3 mana, 2/2 - Bad stats for a 3 mana minion, but ANY card you play gives it a boost. Since Rogue has a lot of cheap spells, together with Conceal and Gadgetzan Auctioneer this one could easily eliminate opponent singlehandedly in the course of two turns. Looks bad on paper, but it was and is one of the best (if not the best) cards that have +1/+1 mechanic.

Math: You need to play two cards after dropping it to make it above average for its cost which may be too much, but it can be any two cards, which is not too hard.

Unbound Elemental - 3 mana, 2/4 - Decent stats, not easy to remove on the turn it's played. I thought this one will be a blast, especially with Lava Shock and Eternal Sentinel in your hand. Turned out not so good as you really don't want to have that much overload stuff in the game as you may happen not to draw Lava Shock or Eternal Sentinel and then you're basically screwed. Plus, it doesn't matter how much overload do you actually put on yourself, like Tunnel Trogg adding locked crystals to it's attack, but how many overload cards you play, which is quite a downside.

Math: Nice stats, as soon as you play one overload card, it's already worthwhile.

I know there are also Tiny Knight of Evil and Crowd Favorite (and some other like Tunnel Trogg and Red Mana Wyrm but let's hold on to those cards that buff both health and attack), but discarding cards for +1/+1 gain and playing battlecry minions is not quite fitting for comparison since they're too limiting.

Now, we have our friend Mistwraith - 4 mana, 3/5 - In terms of cost, this can be easily compared to Unbound Elemental, with all the stats and costed just bumped up by one. May not seem like much, but it makes a lot of difference. Turn 4 is a really tricky one, there's a great chance your opponent probably stumped a big body on board. Luckily, Rogue is pretty good at controlling board in early turns, but more and more the game progresses, the lesser chances are of the minion surviving to gain benefits of the snowball effect. That's why Secretkeeper is good, that's why Tunnel Trogg and Mana Wyrm are good and cards like Unbound Elemental don't see any play.

Of course, there's also the limitation of using the echo cards to buff it up. While not having a negative effect like overload, the cheapest one for Rogue costs two mana. It can't be played like Questing Adventurer which sole purpose is to survive (usually under Conceal) until you start cycling, buff it and hit face. So, how can it be played? Using two echo cards on turn 5 to buff it to 5/7? At turn 5, people are already dropping some serious game changing threats like Cobalt Scalebane and Despicable Dreadlord which can be only removed (if you want to use echo cards) by two Cheap Shots and a dagger ping, which will get you down by 4-5 health.

All in all, doesn't seem quite good when played on curve, it's too expensive for a meta when you can get well punished really quick. Maybe not a bad topdeck which you can drop on 10 and buff it to 6/8, but i don't think that's not what Rogue is about, nor will it ever be.

Great stats, I think this is gonna be played in all rogue echo based decks

Quality of this card will completely depend on if there's enough quality echo cards.

This card has anti-synergy with my Echo cards on the turn I play it, because I have 4 less mana to play those cards. Is it worth crippling my Echo cards for the sake of reliably buffing this minion? I don't see how it could be.