make feats so they are high reward, hard to get, and hard to use(the catapult one for example). off course there are the "smaller" feats, like the shurikens, but they are not that powerful, and that is great.

make feats so they give you that help, either if it is on damage or defense or utility, but dont make them like COD's kill streaks like, kill 5 guys and you never die again with dogs. make Feats so the opponent can anticipate and dodge too.

TL;DR: make it balanced