Breakdown GWM, SS, PAM, Sentinel, Shield Master, CBE, Slasher, Crusher, Piercer, etc into smaller parts and make them free maneuvers similar to what cantrips are for casters. There would probably a one maneuver per attack rule with exceptions for things like Crusher, Piercer, and Slasher.
Fighters start with the most and get the most over time. Paladins, Rangers, Monks, Barbarians, and Rogues start with none because their classes have built-in maneuvers (smites, hunter's mark, martial arts, rage, and sneak attack). They end up getting some over time.
Some of the BM maneuvers get thrown into the basic maneuver list. In return the BM gets more maneuvers than anyone else and gets their pool of dice to increase some aspect of the attack or their character when they use a maneuver (attack, damage, AC, maneuver DC, skill check, etc). Kind of like bardic inspiration.
Some subclasses need to be rethought. BM is losing their unique maneuver list, but makes up for it with extra goodies. Banneret needs to separate their unique abilities from the main class abilities so that they can use action surge and second wind without feeling like their wasting them if no one else can benefit. Arcane Archer is a good idea, but lacks in execution.
With these other changes I'd probably leave Champion, Samurai, Cavalier, RK, Psi Warrior, and EK alone. Or only make minor changes instead of larger overhauls like I'd do with the others.