Not that I think he'll be playable, but they could do something.
He's obviously set up to be another floater like kirby, meta knight, and pit.
He could have a needle throwing special move, because he's theoretically popping the baddies balloons in the original game with a needle.
He could have a shield move where he uses one of his balloons to block an attack. The explosion of the popping balloon could do bomb calibur damage to anyone in range. The catch would be that this move could only be used twice per life (for his two balloons). After the first time, his floating could be weakened. After the second time, he can't float at all.
Maybe do another move in the same vein where he deflates one of his balloons for a massive damage projectile attack that can only be used twice per stock.
Maybe have his b-up move re-inflate some of his balloons but have it take long enough that it's tough to do without getting hit and interrupted.
Tie all that together with a pair system similar to the climbers, and I'm sure you could go off of that.
I think it'd be cool.