In Super Smash Bros. for the N64, Donkey's Green had greenish skin. It'd be cool if there was a way to reflect that without looking nasty. His white swap needs blue tie so it relates to the Super Kong and the blue Boxer DK.
Diddy's red fur on his green palette seems to clash, I think it should be switched out for a nice yellow. If the Green gets the yellow, the blue should get white, partly to match Super Kong, partly for more distinguishingismness. White seems more blue than yellow does.
I think the red team Popo should be a different colour... Maybe orange, yellow, or a less blue white.
The blue palettes for the Mario bros. could have silver buttons, but I don't think they need much change.
Maybe his red could be less black, maybe more pink or orange.
Meta Knight's blue is not very blue at all. Either his default swap should be more blue-ified, and used for the blue team, or the blue Meta Knight should have a more blue body. Or the jewel and the blade could reflect the palette: In my build, Meta Knight's sword has a gem to resemble the colour of the swap, and the blade itself is the same two colours as his shoes.
BRING BACK OLIMAR'S SMOKEY HELMET. He can have dark skin under that, that's my favourite swap. Since a purple swap was added, they could make his blue more blue.
The red scarf for the green swap seems out of nowhere to me. Maybe the colour of his scarf and tunic for his red swap should switch colours. The wings should be closer to the swaps.
I don't like his green and red swaps at all, maybe they're too red and too green, I dunno. I don't know how people feel about his blue, but the Project M team could replace it with his white swap for the blue team to make room for a costume, should they want it to have team colours.
Green ROB should have a blue cord.
Pink's not very red, but I don't know how they could fix it. In my build, the green and blue are closer to the Metroid Prime 2 echoes multiplayer, although darker, I find them more friendly to the Metroid series.
They could change the colour of his shield for each swap. In my build, the red, blue, and purple have the four-sword.
I don't like Warioware Wario as much as awesome Wario, but his red and red/black swaps are too similar. Maybe the reds in the red/black could be moved over to his read swap, and replaced in his black swap with purple. I am now doing that in my build.
Wings in Dragon Yoshi should reflect his current swap.
I think Sheik's red scarf on his blue is weird. I wish he was more red on his red team.
In my build, I made the blue reference the dark samus swap, by adding some black bits from the black swap, and the pink glowey bits orange. I want to make it better but don't know how. I think the glowey bits should relate to the glowey bits on the Suit in question: Pink and purple gets blue, black gets red, green gets yellow. I also made the handle of her paralyzer relate to her palette swap.
Mewtwo needs his orange palette swap.
MEWTWO NEEDS HIS ORANGE PALETTE SWAP.