@Rocklee10: Pokemon may be an anime, but that's not why it's in Smash. It's in smash because it's one of Nintendo's best-selling series after Mario. There are also manga and/or anime for Zelda, Kirby, Metroid I think, maybe others. But they aren't in because of that. It's because they're all big for Nintendo as game series.
While I'm far from anti-anime/manga, I do not want it to cross with Smash. The very nature of the biggest animes out there, like Naruto and Bleach these days, gives them lots of viable characters. But at the same time, it's not the same thing. Also, the idea of Smash is Nintendo's biggest stars fighting for no apparent reason. Anime characters are not Nintendo stars, even if they have been on Nintendo games. Snake and Sonic are not Nintendo characters, but Snake started there, and Sonic's ended up there recently. Also, Sonic's direct competition with Mario in the olden days certainly made him even more popular.
Mario is due for a little boost, though. As for your suggestions, I'd say keep his Dair, but just make his Fair a more useful spike, maybe making it slightly faster or something.