For what it's worth, the game runs smooth on my older iPad 4. I haven't seen any issues where it didn't recognize a touch action, except maybe drag and drop when creating a party.Game is great as expected, though experience not without flaws on iPad Air. Almost every action has a lag, game don't handle touches well - many times I've had to press some card/icon twice to make it work.
Also I noticed that Quest mode doesn't work at all, when I choose normal game app always freezes on loading and I don't know yet how to avoid it.
So I can say that it's very far from polished.
My installation of iOS is out of date, so not sure if that would have anything to do with it.
On a different note, I was thinking of recording a Let's Play/how-to-play walkthrough , and maybe explain some of the game mechanics in more depth. If I get around to it I'll post a link.