Thing is, "barely enough" for jigglypuff in the air doesn't cut is. She has the worst ground game in the game, hands-down, no argument. She can't WoP combo, mainly because it doesn't actually combo. The opponent can get out if they know what they're doing. She can't WoP strategy, because she doesn't have the mobility to weave in and out of the opponent's range at all. Her attacks are easily punishable because of her bad mobility. You can shield and run in before the attack lag finishes and punish. With mobility, she'd already have retreated far enough that almost nobody can punish. She dies laughably easy as the lightest character in the game, and she's really just a one-trick pony. Utilt/Uair > Rest is all she's really good for. You want WoP combos? Kirby, DDD, metaknight. You want onstage aerial ****? Squirtle, Wario, Luigi. She has Rest. And sooner or later, a one-trick pony is going to become worthless, especially once the rest of the cast is balanced and people learn how to deal with Rest.
leafgreen: nair>rest and bair>rest already work. Increased aerial mobility wouldn't make it work any better or add any new rest combos. Besides, bair>uair>utilt/uair>rest is a lot better. All increased aerial mobility would do is make her weaving-in-and-out WoP a lot better so that she doesn't get punished for trying to approach.
And I don't care how good her grab game is, the fact is that all they do is put the character in the air. Yes, that is good, since she's an aerial character, but you still can't combo, kill, or really do anything with them except put them in the air. And considering that her ground game is bad to the point of complete non-existence, well, you'd expect her to have at least something decent.
