I also have a Kirby request, if you activate Stone while running I wish the stone would slide forward a little for some minor damage/knockback like in Kirby games.
I don't think he needs to be much bigger if at all but he needs to have a bigger hurtbox.
If kept as is I'd say make him even lighter than Jigglypuff to compensate, something's gotta give.
Waluigi was built for PM and a Brawl version came later. The creator had no intention of Waluigi being in Brawl Minus, we (not me, the guys who do the real work like ASF1nk/Sammi) took his finished work and adapted it.
That's what we do for every character though, I'm just about 100% sure...