Please provide a means for players to at least reset their skill trees for "free" once in a while. Even if at an insanely high in-game currency cost or something. Right now it feels awful knowing that if you make a mistake when starting out you really can't do anything about it - unless you get that card out.
It's definitely one of the worst systems I've seen in a while. It is the type of thing I expect in a mobile game, not in a proper console/pc game.
The game is super fun and I'm not against buying stuff in it. I just think that the skill tree stuff is way too far and over the top. Just plain excessive and not necessary.