I expect to see:
Mario: Bowser Jr(dont like em, if he takes off that scarf I might find him cool)
F-Zero: Samurai Goro(like him)
Yoshi: Kamek(love him!)
Metroid: Ridley(LOVE HIM!)
Pokemon: Zoroark and Mewtwo
Star Fox: Crystal(not sure how I feel about this one, but she would bring a fun moveset to the game)
DK: Dixie Kong(I will repeat this until confirmed, I figure if you keep saying something long enough it comes true)
Punch Out: Little Mac(He better be in this game)
Anyone else not sure, but these guys are most deserving. Yes I think Kamek deserves a shot, he went from cool looking enemy you see in castles to a constant nemesis for Yoshi with dialogue!