Sir Louie Onyx said:
1. Geno (Super Mario RPG - Legend Of The Seven Stars.)
The long lost hero from the Super Mario RPG, his attacks were overpowered, but that's why everyone loves him!
No-one cares. This has been the most overhyped fan-addition to SSB since SSBM came out. Only 6 people actually played Super Mario RPG and only 3 of those actually liked it. Some obscure random character from it that hasn't been in
any other Mario game ever doesn't cut it as being worthy of a spot in SSB.
2. Louie (Pikmin 2)
Olimar's hungry sidekick, I think he would kick ass in SSB. And he is the reason I am called Sir Louie Onyx.
Olimar and the Pikmin themselves are more than enough, really. His sidekick could only be a clone of Olimar, and considering Olimar's pretty lame in and of himself, the world could live without two of them. Maybe just introduce him as a reskin of Olimar or something ala Wario or Zero Suit Samus. That'd be more than enough.
3. Bomberman (Bomberman Series)
I don't know much about him, but he looks kinda cool and as Morshu said: Bombs.
I don't want many more third party mascots added to SSB because I think it'll cheapen the series. That said, Bomberman and Megaman are the two must-haves if we're going to have
any to go alongside Sonic and Snake.
4. Banjo and Kazooie (Banjo Kazooie series)
The bear and bird are back! They have awesome games (Except the Xbox version, that was a pile of bull) and could glide.
This just isn't going to happen. Microsoft owns the IP and while including characters from third party companies obviously isn't off limits, including characters from a hardware rival isn't gonna happen.
Also Megaman, Starfy, Duster and Sukapon. Now, who do you want for the next game?
Aside from Megaman, covered above, only Starfy of those would be worthy of a spot. And even then, it's kinda pushing it. Starfy's success outside of Japan has been incredibly limited and while that didn't stop them including Mother or Fire Emblem characters, it's hardly as if Starfy is on their level even in Japan. He made a good Assist Trophy in Brawl and I can't see much call for him being upgraded to the main roster.
My own picks would be something along the lines of this:
A Metroid Hunter: They haven't been in much, and were only really introduced as a gimmick for the DS game Metroid Prime Hunters - BUT, they are pretty much the closest we've gotten to a non Samus playable character in the Metroid universe, and since Ridley is pretty much never going to make it on the playlist, they'd be the best available choice for giving Metroid another character to play with.
Zoroark and/or Blaziken: They're just the two Pokemon I see fitting the best in the game. I'd like them to keep Lucario in there too (and I wouldn't be disappointed if Mewtwo returned), but either of these two would make a good addition to the next Smash Bros. Blaziken would be nice purely on the grounds of giving Gen III some love in the game for once, and considering the next game may not be around for a while, it's possible that the most recent Pokemon game by then may well be an R/S/E remake anyway.
Another Pokemon Trainer: I don't really care which generation this trainer represents, but I do want a second trainer with a second set of starters. If they replaced the existing one with a new set, I'd live, but I'd rather have two sets of Trainers. Just call them by their 'game' or manga names. Red and Gold or whatever.
Isaac: Long overdue as a playable character and a perfect mix of sword/melee and magic/projectile gameplay just waiting to be tapped.
Vaati: I saw a list along this line a while back and they suggested Vaati, the magician villain from Minish Cap and 4 Swords as a good choice for a new Zelda character. I have to say that I completely agree. He's got the same style that would work well alongside Toon Link and, like Isaac, comes pre-packaged with sword/melee based attacks and magic/projectile attacks too. A lot of people will push for Wolf Link/Midna as a new Zelda character, but I'd much rather have Vaati.