While I don't play Hearthstone personally, I enjoy watching it and seeing the meta shift and I love the look and story of this expansion. Everyone calls it hentai but I appreciate the Lovecraft inspiration, especially for someone like me who has been playing a lot of Bloodborne recently.
Considering the few cards that have been announced, I'm really excited seeing C'Thun in action and the passive buffing it receives in the background from some cards triggering it, especially if it combos with Bran. Even the cards that buff it have good stats I think for their mana cost. I also like the new Doomsayer, though I'm not really sure if its actually good or not in actual gameplay. It looks like Priest benefits a lot from these new cards so that's interesting.
All in all, looking great in my opinion. Than again, I don't actually play the game so I might be speaking nonsense for all I know. lol