Hearthpwn

Amazing counter to zoo and token, and slightly aggro. But requires them to be 70% of the decks you run into. So a midrange meta will make this kind of card useless.

Wow, scilencing or transforming this minion is super useful, and evolving is stupidly good (if you hit an enemy). It can also be used to save a low health minion of yours. It's a unique way to make your minion sticky, and it can heal it or remove debuff on the way. (quite anti tempo though)

With how the text is written, yes, he will.
Order of actions:
Moat lurker kills sylvanas when she was on the enemy's side, that information is kept with the ability in the deathrattle.
sylvanas trigger
Moat lurker switches to the other side, deathrattle unchanged.
He dies, deathrattle triggers: Resummon sylvanas to board X

I hear it for any priest card releasing, trump is there even when you don't want him ;)

That would require a whole new UI for looking and picking one from ALL the friendly minions who died. We didn't see them experimenting with something like that in tavarn brawl, so the likelyhood of them making a special UI in level of attention equal to the discover mechanic, is pretty unlikely, especially when this is the only card that will have such an effect.
But they really need to change the wording if that's the case.

Oh... Oh wow... I, I wasn't expecting an actual good beast synergy card...
That's pretty scary, if you are up against a druid in late game ,and you fail to kill his high stat value beast, you are pretty much fucked.
I would have called this card pretty strong even if it was "chooses a random beast and copies it" but you actually pick for yourself. Beast druid might become a thing now.

Secret decks will need to be EVERYWHERE to make eater of secrets worth even as a one kind in a deck.

Battlecry activates after the card is played, and when a card is in play, it's not in your hand, hence, the battlecry won't work.
It was a cute attempt to be witty, but you clearly know nothing john snow.

This card opens up so many paths for the druid:
1) Amazing early game plays! After zombie cho left with the rotation, we started relying more on class cards to get a good early. Druid already have living roots in his arsenal, which means we can have a very consistant early game if you can moligan to any one of your early game plays.
2) Beast druid? This combo alone of raven and mark can prove to be strong enough to make 2 marks viable, which means putting beasts is suddenly better. I think that we just need one more beast synergy and this deck will become crazy viable.
3) God forbid, but maybe aggro, this card is annoying to get rid of because he has more than one hp, but the fact that he has 2 damage can cause a really long term damage. I can easily see the raven dishing an average of 6 damage a game if played on turn 1, which is pretty close to how the leper gnome faired in aggro.

This card might be able to give druid another push forward.

Seems really slow, unless you find yourself consistantly running into late game, then you won't need this random carddraw

If I've seen enough metas shifting, I'm sure that a solid counter to C'thun will crop up in the future. Though, I can't believe a strong counter to C'thun will stand without obvious weaknesses, which means it's not a stable counter, therefor it's still worth to have a C'thun deck on standby. I suspect that it's worth throwing 1600 dust for this card, as it makes an entire C'thun deck twice as strong, and I don't think the meta will shift very soon, at least it will hold until the next expansion.

Thank god it's only for C'thun decks, Dr. 7 was broken because it was so easy to just put him in a deck as a general late game card no matter what. But a card like that is what makes C'thun decks as strong as they are.

C'Thun should be played after the twins if it's in your hand and you have the two pieces for this combo, as you said, the chances of brann's survival are great unless the other guy is going to play a strong god play.

Battlecry: Give each player an empty mana crystal.

I really like that idea nic, as you are taking a risk by letting your enemy enjoy the ramp first, if he had an efficient answer to your golem, and that ramp allowed it being played next to another drop, then you lose all your tempo. But if he planned his curve, and you adding another mana have messed his plan, then its a great bonus to get a 4/4 on the board for only 3 mana.
Blizz really like to nerf cards hard, and it makes me sad that a card is suddenly unplayable (for example: warsong), when it had the potential to become something less toxic yes somewhat playable.

requires 5 cards for the combo, and to survive until the combo turn which is way after turn 10. Its an awesome turn, but you will need 20 games to get this combo to happen.