I know it would be quite hard to balance, but I'd like characters to have flashy improvements on some of their most iconic moves, when their power gauge is filled. This "Power Move" would exist in addition to their universal PBs and PLs. The idea is to give the roster more diversity and highlight each fighter's individuality.
Technically, it means more damage or new properties. Esthetically, it just means alternative animations, a slow-motion and some optional customizable effects (butterflies, wind, water, etc).
Compared to "stable" PBs and PLs, these moves are more situational in terms of imput, rewarding because they don't stop the action but gives advantage, and don't have universal damage (can be hi counter). Also, they should feel epic, exciting and rewarding during a match. This is not a reversal mechanic, more like a specific trump card that define the character.
Examples (all moves are in slow-mo): Mila's tackles (1.5x damage and one additional punch), Bayman's Hell Suplex (1.4x damage, second part ends with a garanteed ground throw), Lisa's Deja Vu (1.3x damage keeps holding the opponent's head with her feet instead of launching it, stands up, stomps the opponent's head and does the pose she uses in her tag victory pose with Ein), Helena's 236P+K (1.2x damage, sit down stun and BKO dash and 22 is faster for a few seconds), Raidou's Torn Sky Blast (stuns the ennemy for a few seconds), etc.
What a mess to balance...