Pit was only in two games, yet here he is again, nearly 20 years after his last game, and they made him a playable character. As for characters who don't have a lot of powers, that's just silly. Before the SSB series, Capt. Falcon was just a racecar driver. I'm sure that if someone had suggested him before the first SSB game, people would have repsonded with "What would he do? Run over people in his car?"
If they can come up with moves for characters that have never been fighters, they can come up with moves for characters that haven't had a lot of screen time (ie: Pit, Toad, etc..)