One small problem I found with the campaign is when you have an ai on your team, they often get in the way. It would be nice if the game let you place your cards before the ai was able to. I've lost 2 games so far in higher level campaign because I wasn't able to play a backstab or vigilance due to a friendly ai block
Would have given it a 5 star vs 4 star if the pvp was more balnced. Right now I get paired with levels 15+ higher than me and as much as 300 more battle points than me. The fact is, the higher the level, the better the cards. Pvp's just not that fun atm