I am curious about the Up Special recover attacks.
I would love IvySaur to have a whip attack that can attach to ledges and even people to slingshot quickly back up to the playing field.
Obviously, Charizard can and will fly somewhat for recovery. I have no idea how Squirtle will recover.
I am hoping that Squirtle is a fast character that can speed around almost as fast as Pikachu and Ivysaur be a mid-weight character with pretty weak jumping skills. Finally Charizard will be a monster heavy weight with huge jumping and flight potential, but perhaps his Stamina drops faster.
Also on discussion of Pokemon management, it would be cool if certain attacks are designed to hurt certain Pokemon more.
Squirtle should be very vunerable to electric attacks, but perhaps could hurt or counter fire attacks with his water.
Ivysaur would be very vunerable to fire attacks from Bowser, but pikachu's electric attacks would do less damage.
Finally, Charizard would be vunerable to water attacks, and perhaps pyschic attacks from Ness.
It would add some fun Pokemon strategy to the game, even if it doesn't always come up into play during matches.