the game is really nice, here are some ideas to improve it
1) Since it is not possible (yet) to recover a replaced weapon, what about the possibility to change weapons between two cards of the same type?
2) A expansion map/area (something like isendel area - dream world)
3) a "super-charger" to speedup time needed to recover stamina,
4) 7 star cards - hybrid cards. With 2 max-evolved 6-star cards of different types, they can be fused in a superb 7 star card (something like the two-color dragons - dragon era)
5) more card's tavern missions, alone or with guild
Olimpus