I'm now very curious to see all the class C'Thun cards. I didn't think much of C'Thun decks (Blizzard has pushed Beast Druid, Dragon Paladin, Bolster Warrior a lot and they've not been very good) but C'Thun decks might end up being the real deal.
Ben Brode was noting that they wanted to push a lot of the power in the game into class cards going forward, so I expect the other ones are quite good too.