Not sure how possible it would be, but it'd be cool if it was possible to have more freeform guidelines around creating a character's power moves and other abilities using some sort of tag effect system (similar to how a player can design the character's weapons around tags that cover damage, range, and other descriptors that add logic to how the character can interact with the fiction (and how the fiction reacts to them). For balance, they could work on a benefit / limitation (or cost) system.
Saying that, power moves (as they currently function) might be too complex for something as freeform like that, so not sure that could work, but wanted to suggest it just in case.