There's a tiny bit of information in this interview here...

What I got from it:
- Card selection sounds random. Or, considering that you apparently need quick reflexes, you might be spinning a wheel and the same reflexes will help you in picking the Card you want.
- Cards will seem to mostly be about buffs and supporting your party (more buffs, or debuffs on enemies?).
- Cards can be stockpiled instead of being used up immediately, perhaps allowing for some fancy combination spells!