Mario: it's OK but make it useful maybe? Even though MegaMario would probably be more actual.
Luigi: something about Luigi's Mansion. That one needs to change asap. Just make it about ghosts please.
Peach: perfect.
Bowser: ditch Giga, we want the Koopa Klown Car.
Donkey Kong: I love it, but make it stronger.
Diddy Kong: it's perfect.
Yoshi: eh, I don't know. It's good but could be better, no idea how though.
Wario: perfect.
Link: it's... OK, I guess. Could be better.
Zelda/Sheik: it works, but would be nice if different between the two. Maybe something involving the Ocarina for Sheik.
Ganondorf: he needs to transform in Pig Ganon à-la Wario-Man.
Toon Link: jumps on the King Of Red Lions and shoots bombs (similar to Snake), or maybe something involving the wind.
Kirby: funny, but a little weak. Buff it up.
Metaknight: the worst after Lucario. Come on Sakurai, you ****ing INVENTED Metaknight. Don't tell me you can't come up with something better.
King Dedede: it's funny but I can't accept it can't be better. Doesn't he have, I don't know, some machine or something like that?
Samus: it's perfect and also we know it is the same, so.
Zero Suit: don't really know, the Brawl one sucks though. Something related to her spaceship?
Pikachu: it's nice, but a thunderstorm on the entire stage would be more epic.
Pokémon Trainer: good idea, but the realization is sloppy. Make it prettier and maybe with different effects depending on which pokémon launches it.
Lucario: for the love of God get rid of that ****. MegaLucario time.
Jigglypuff: it's perfect.
Fox: it's perfect.
Falco: jumps on an airwing and shoots on people (similar to Snake but with more freedom to go around I guess).
Wolf: something something landmaster ****ing Team Wolf storms the place. MAYBE Pigma like he appeared in Assault could appear and kill everyone, even if it doesn't make sense character and story-wise would be cool.
Captain Falcon: it's neat, needs to be prettier and stronger. Maybe with different tracks which appear.
Olimar: same as above, but the idea behind it is one of the best of the entire game regarding final smashes.
Pit: gets his Uprising armor / rifle, shoots people up. His Brawl one could go to Palutena.
Mr. Game & Watch: good idea, awful result. Just get it work
R.O.B.: boring as hell, but I have no idea what he could actually do.He could maybe summon the Professor or some ****? Don't know.
Lucas & Ness: I don't know Earthbound but at least one should change. I mean, I'm OK with semi-clones, but the damn final smashes at least.
Ike: it's pretty good, I like it.
Marth: Well that sucks. Come on make him summon some of his friends. Maybe Roy (LOL)
Ice Climbers: it's neat but imho something about polar bears or the condor would be funnier.
Sonic: it's perfect, just needs to be nerfed a little.
Snake: it's OK but I don't really know MGS.
Man a lot of them need to be redone really.