Earthbound, how can you say that she is "nerfed slightly in the air, nothing big" seriously? In melee she could fight on par with any of the best characters in the game whereas in brawl she gets KO'ed ridiculously easily, is unable to combo well (like everyone else), and can get camped all day long by projectiles. Also, the general speed of the game makes jigglypuff at a relative disadvantage because she is relatively predictable. Furthermore, the inability to L-cancel allows someone to shield an aerial with impunity.
Jigglypuff is nerfed into the ground.
EDIT: and the inability to wavedash or even dash well hurts her significantly on the ground. Also her up-smash is relatively useless against a decent player and her down-smash seems to be slower.