Samus - 100%
Samus is star of the Metroid series - probably Nintendo's fifth most popular (if not fifth biggest) franchise currently featured in Smash Bros., behind Kirby, Legend of Zelda, Pokemon, and Mario. There's no reason she should go whatsoever.
What else is Samus but deserving (5)?
Paper Mario - 70%
To be honest, I think Paper Mario's chances are underrated, and he himself is the underrated possible new Mario rep. I hear talk everywhere about Toad, and Bowser Jr. is nearly universally found on rosters, but Paper Mario gets only occasional attention.
So what helps Paper Mario's chances? Firstly, his spin-off series, Paper Mario, has been growing since it's first release on the N64 and is as important as the Yoshi series at this point, really (not quite up to Wario or Donkey Kong standards, though). That game is being remade for 3DS this year, so Sakurai will look at what is recent when he considers characters (much like how Victini is possible), and Paper Mario's upcoming game will help raise his chances with Sakurai.
A semi-clone of Mario? Impossible! Paper Mario rarely uses any of the moves Mario is known for in his games. It's possible, but I doubt Sakurai would turn Paper Mario into a clone given how much moveset potential he has.
His only problem is he is neither as popular as Bowser Jr. nor Toad. However, Bowser Jr. is popular in America and Europe; Toad is popular in Japan. Paper Mario is popular in both.
Paper Mario is completely deserving as a new Mario rep, or heck, as a rep of his own spin-off series. As a Mario character, he isn't quite as deserving as Toad, but he has more history than Bowser Jr.
But do I want Paper Mario? To be honest, while I love the guy and his games, I want to complete representation for the Mario series, so I want Toad and if possible, Bowser Jr. in there too. And since I personally categorize Paper Mario as different, he falls under the "new franchise" factor that Isaac, Starfy, and others are fighting for.
The real thing that confuses me, though, is even then, I for whatever unknown reason, am against him, even if we get an over-50-slot roster. I love his games, but I don't want him in Smash Bros. I cannot explain this dislike. He should get a Wanted from me, but for this god-forsaken reason, (edit) I've realized he only warrants an unwanted (2) from me.
My Nominations:
Veterans
Bowser x5
Newcomers
Tetris Block x5
My Predictions:
Saki - 70%