Hearthpwn

I have been testing different types of Cthun druid - my favorite deck of the expansion. After trying different cards and archetypes, I came to conclusion that you don't need any kind of "backup plan" or other win conditions. The best strategy is to go all-in for multiple C'thun, cause there are usually nothing that survives 2 of them. 

Stategy:

• Mulligan for Ramp, always keep Guff. You can keep 1 removal spell vs aggro
• After you ramp, draw, draw, draw
• Stabilize with Solar Eclipse + Cenarion Ward
• You can use 1 copy of Moonlit Guidance to search for Guff if you haven't draw him yet. After you play Wildheart Guff, do 2-3 turns with ramps, then draw only. Remember, Guff HP gives you a full mana crystal, so if you have 3 mana left, you can HP+play Guess the Weight
• Use Auctioneer + cheap spells to draw the rest of your deck
• After you complete Cthun, you should have only 2-4 cards left
• Try to use Forest Warden Omu the same turn you complete Cthun. Then use Moonlit Guidance to tutor the copy of it and play the same turn
• Win

In best case scenario, you are able to draw the whole deck, complete and play Cthun by turn 8-9. You will have 16-17 mana.

The weakness: paladin. Too many divine shield gigantic minions + trogg. After nefrs it should be better. Tickatus warlock has been on the rise recently, as well. 

Let me know how you do with it. Enjoy!