Hearthpwn

It's not impossible.  Play shaman with Al'Akir, Yogg can get you this secret.  Or play as hunter, play Yogg when your opponent has Al'Akir out, Yogg gives you two mana via innervate, and casts shadow madness on Al'Akir.  Then you play brewmaster on Al'Akir...  Clearly a synergy worth building a deck around!

Don't forget about ice rager!  Together, they'll be meta-defining!

Which never saw play...Yea, don't think we'll be seeing this one played much, though it does gain more and is cheaper, so you never know.

If only it were return a friendly character to your hand, you could put yourself in your hand and hide out there until fatigue, if you were willing to forego use of your weapon.

Maybe if it gave you a coin for your effort, it would be useful?

Erm...They're both class cards.

Yea, even given the new effect, too bad they couldn't come up with more interesting ways to use it.  Give spell damage or taunt (+can't be targeted by spells).  Reduce cost of a random spell by 1.  Give a random beast charge.  Make a random non-pirate minion talk like a pirate, etc.

Now if only this card gave a random murloc in your hand a mustache, I think the card would single-handedly make murloc decks top tier.

You've clearly never met an usher of souls in a dark alley at night.  Trust me, not friendly.

Common sense?  Wouldn't that only apply to common cards?  You'd have to use your legendary sense for this one.

I think that's too useful.  I'm thinking priest will get a 4/5 for 8 mana, with the text:  "Battlecry: Silence a possessed villager".  Card would be almost as good as Light's Champion.

Silverback Patriarch cries in a corner...

I wonder how long we will need to wait until someone will get rekt by 4 or 5 of those at turn 3 in arena.

I hope Kripp will be a victim of it as some point >:)

Super good in Arena. Win if you're ahead, have a fighting chance when not.

In constructed.... You don't need this. The concede button is neutral, 0mana, and doesn't waste a card slot.

Knights of the Frozen Throne is secretly turning into Lich King vs Battle Pets with all these adorable cards getting released.

o.0

This + Treachery :D

Meta defining would imply, that next to all decks are running it, no? Or rather, that there will be an influx of new decks with tier 1 potential using this card.

In my honest opinion, this card is very good, especially for priest, but still falls short of being meta defining. You don't need a specific counter against it, and sometimes it won't even hurt to let it lay for a few turns (though that may be very dangerous, with all the health buffs and whatnot). I can see some Minion focused decks paying it, since it does scream value overall. 

In Arena, this thing will become bonkers, I reckon. Especially if you can protect it, and the enemy is out of removals.... I can imagine some scary dream-like plays with:
Northshire Cleric -> Shadow Ascendant -> Acolyte of Agony / Tar Creeper / Stonehill Defender. That can easily close a game, since nothing short of a boardwipe will get you enough tempo to return. All your minions you play will be understated (due to Shadow), and the healing of priest gives him even more control, as well as cards....