...who else would you put that is female? Palutena, maybe, and then who? Toon Zelda?
Villians could certainly stand to have more representation, although Nintendo runs into a bit of a problem since the majority of their famous villains aren't really suited for a fighting game. There's no villain besides Bowser who'd be worth putting in from Mario (added to the fact that the Mario series already has plenty of representation), Metroid's villains have size issues (Ridley) or rooted to the ground issues (Mother Brain), Fire Emblem's main villain changes each game, Star Fox has size issues (Andross), and a massive case of clone syndrome (Wolf), Pikmin doesn't really have any memorable villains (and they're all too large even if they were), Kid Icarus has Medusa which again runs into size trouble, not sure who could go in from F-Zero (and how you would even come up with a moveset for them), and the only real "villains" in Pokemon are human.
Zelda, of course, has Ganondorf, who I'd be fine with if he gets a drastically altered moveset (at least the Fox clones were somewhat different). Ghirahim would be an interesting addition, but the game seems to be leaning pretty heavily towards rushdown characters at this point. Skull Kid would be crazy addition that I think I would prefer before those two; not sure what in the world you would do for his moveset, but he's Skull Kid, so preferably something suitably creepy (or, at least, this would all be great if he wasn't a confirmed assist trophy).
One villain I would absolutely love to see included is some iteration of King K. Rool; he's honestly probably the biggest name Nintendo villain outside of Ridley that hasn't appeared in Smash Bros yet. He doesn't have anywhere near the size issues that Ridley does; his moveset would be fairly easy to take from the games (especially if they went with his Kaptain K. Rool variant), and a final smash where Kremings went all over the screen would be too great to pass up.
Other than that, Dark Samus would've been a great Metroid villain to add, but, y'know, assist trophy.
