I've been wondering, since Power-based moves to hit stamina are weak, why not turn them into %max stamina damages, with a base % hit to stamina, affected by Power and by Ki? Perhaps, make Power-based moves hurt for a flat calculation, and make Ki-based moves hurt for a %? That would allow Stamina-specialising persons, like Jewel, to remain competitive middle/late-game by scaling vs higher levels when she gets Ki. At the same time, the high level of Ki needed will mean that other characters can't just start using power moves because they got buffed - without investing in Ki, they don't hurt as hard.
However, seeing as a lot of red moves are power-based, perhaps Ki can add a small % to those moves too. The point is to scale damage, like in (sorry to bring it here) Blade of the Ruined King in LoL, which is used to shred tanks easier.
You can even think about making it Jewel-exclusive by giving a trait to help. Similarly, testosterone can be changed to giving Power proportional to how much Ki you have, instead of giving just extra Power (at least, that's what I think it does.)
That could end up being the basis of jewel's addiction, Ki moves.
I just want to see the characters be a bit more balanced - I had a match with Jewel which displayed her potential - lock ups and stuns with dominance, then make the opponent orgasm. This change would help achieve that by making red moves valuable for her.