Mewtwo's Smash attacks really should be a lot more powerful, and have a lot more range and overall coverage. His grab range also needs massive buffs, same with stats as weight and speed. The tail hitbox also need some serious fixing.
Fun how you liked DK and Mewtwo the most in Melee btw, they are my favorites to!
I'm not sure Mewtwo's weight needs fixing, really. He's a light-to-medium weight, which I feel compliments his anti-gravity psychic antics.
I agree that attack balancing and hitboxes could use some adjustments... Maybe even a new attack or two. But you can rest easy, there: if Mewtwo comes back, it's guarenteed to get that treatment. Just look at the admirable job they've been doing with most of the other characters! Smash 4 seems to be delivering on a lot of fans' wish lists, so far.
Watching a couple Project M videos with Mewtwo in them gets me really excited, though. It feels like it's been eons since Taj made a M2 combo video, or since M2K actually used Mewtwo, for that matter. I never got into the tourney scene in Melee, but both of them were an inspiration to me. I'm not sure I support PM, but the new life it has breathed into Mewtwo is hard to deny. Hopefully Smash 4 will satisfy my desire to kick some tail with M2 again so I won't have to look to a fan mod to scratch that itch.
Ugh, I can't wait to get my hands on Smash 4. I'm really hopeful that it's going to be enjoyable, competitive, and a tad slower than Melee. Melee was fantastic, but I felt like it was almost too fast, really, while Brawl was way too slow.
********EDIT
Instead of double posting, I'll just ammend this thought: how will they handle Mewtwo in a game with multiple air dodges?
In Project M, the old Mewtwo feel right at home, due to the old Melee air dodge mechanics being present. But, in Smash 4, I'm not sure they'll keep Mewtwo's invisible air dodge per se. They might, and that could be quite a serious buff in itself, but being able to travel trough the air while remaining largely invisible is quite a serious balance consideration.
What are your thoughts?