Are there needed buffs we can ALL agree with? Ones without a doubt?
Weight.
Up air, back air, and up tilt fixing their animation/hitxboxes to make them easier to hit.
Down smash having a bigger hitbox, particularly against rolelrs.
Confusion. Change hitbox or faster start up.
-overall faster tail attacks(particuarly forward and up tilt, and back air)
Personally I think forward smash shouldn't whiff at point blank. I don't know why people actually think there's no problem with this.
Also, I think Shadowball needs another buff, like damaging opponents while charging.
I know I don't have everything covered.
Also, assuming we have a patch, how do you think Sakurai will balance him? I don't know if I'll be more surprised if he does or doesn't change his weight. At the most so far, sakurai has changed damage values, knockback, and frames. But not an attribute like dash speed, air speed, or weight, IIRC. IF he DOES get a weight buff, I can see it come back to Melee weight. I'd love Mewtwo to be buffed as average weight(95-100) or light heavy, but I don't ever see it happening.
I DO see Mewtwo getting some damage buffs on some of his tail attacks maybe, and less whiffs for some moves(very likely).