Pretty much what Raykz said.
Would also want to see Mewtwo's attacks to have larger hitboxes closer to M2's body. I shouldn't be able to overlap an opponent and not do anything with so many of his moves (B-Air, U-Air, F-Smash, U-Smash), especially when M2's only non-hurtbox is at the trunk of the tail.
U-Smash, in particular, bugs the crap out of me as a Mega Man main.
Disable, IMO, should do some extra shield damage. Though how much depends on how Jab is fixed, to which regardless I think could use a bit more to validate the risk.
D-Throw I'd like to see have less end lag or launch at a more vertical angle so it can be combo'd at lower %s at least.
Weight I would like to see, but only around Rosalina's. Mewtwo's kill buffs I think validate some weight loss, though I still find it disgusting that Luma got back some HP in the latest patch. Regardless I don't think it'll happen nor do I think it's the root of the problem.