Hearthpwn

At first glance, if the idea is to use the quest Hero Power for a double C'Thun, I don't think you should put Galakrond + Kronx in the deck. Because if you complete the quest before being able to play Gala, it becomes a dead card since you don't want to override the quest hero power. These two slots could be filled with 2x Novice Engineer because card draw is important to assemble C'Thun quickly.

Perhaps going more of a control build. Will be hard to get to late game to play Cthun against Demon Hunters, Hunters and Mages. unless you control board and manage to heal along the way. Ditch Galakrond package, Swampqueen etc.  Going to need Tidal Waves and Witchs Brew.

I think you should include Lightning Bloom so you can hp + c'thun on one turn instead of playing the tour guide so you have to wait another turn

I already have lots of healing from fountain, groundkeeper and medic and plenty of removals.  Novice Engineer is good for draw but apart from that it is really really bad. I have cut Hagatha and put Lady V in for quick and cheap draw of C'thun spells

I will make more changes

Quote from Xeze >>

At first glance, if the idea is to use the quest Hero Power for a double C'Thun, I don't think you should put Galakrond + Kronx in the deck. Because if you complete the quest before being able to play Gala, it becomes a dead card since you don't want to override the quest hero power

Oh wow, how stupid of me. I have added two lightning bloom instead

I think C'Thun Shaman needs to go all in on draw battlecries (like Novice Engineers and Harrison Jones and Questing Explorers and even Prize Vendor in addition to Manafeeder Panthara) to have a chance. This probably means cutting the Galakrond package which, as someone else pointed out, conflicts with getting your Quest Reward Hero Power anyway.

C'thun Quest Shaman isn't likely to be a thing, but there IS a really cool OTK with Y'shaarj and the quest. Here is my list on that: 

The goal of this deck is to set up an OTK where you complete the quest and play Tour Guide to make your next hero power free; then, you play Y'Shaarj, the Defiler to get back two free copies of each corrupted card you played, which amounts to up to four Dunk Tank and four Circus Medic. As each Medic's battlecry triggers twice, your four copies hit the opponent for 32, while the Dunk Tanks hit them for 16. If you only played one Medic and one Dunk Tank, you get two of each from Y'shaarj, which only deals 24 damage, but this should be enough to close out a late game. 

I DO NOT think that this will be a significant meta deck, but it should be fun given the dumpster fire that Shaman has been handed this expansion. It should do reasonably well against midrange and control, but I'm concerned that aggressive Demon Hunters are going to be everywhere and this deck won't be able to keep up.

Is anyone else trying the C'Thun quest? I am still working on it. You can see my last version in my starting post. I am slightly above 50% win rate for the moment