I am the type of Smasher that cares more about the big picture, how the character can best represent a series or franchise from which it hails. So to me, the return of FLUDD is a disappointment. Mario Sunshine was NOT his best game by far.
It would've been way cooler to have a down-special like a green-pipe teleport move. Or just keep Mario's first down special- the cyclone spin attack- because at least THAT was of some use, whereas FLUDD is hardly ever useful.
In fact, FLUDD just felt like a lame attempt to make Mario current in Brawl, so why is it back when there is literally ANYTHING from Mario's history that is better- Cat suit, Tanooki suit, he could drive forward in a kart for a short distance, Bee Suit, Ice Flower.... these are all more recent items and I just pulled those ideas out of my head without trying.
OR BETTER YET!! Make use of another classic power-up, like the Raccoon-tail spin attack from Super Mario Bros 3 (NES- classic!) & Super Mario 3D Land (3DS- so current!) What a better way to make Mario a fun, useful, and relevant character?