Yes, pretty much she's an aerial based character in Smash. It doesn't make much sense to try and cut the grounded weakness of hers when that was never too much of a weakness to her in Melee. You don't have to do much to make her back up at High or even Top tier...
Just reinstate Rest as powerful as Melee, allow her to follow-up into it via a throw or techchase situation (i.e techroll predictions, techstands), Bair range slightly disjointed, and Fair hitbox reinstated to how it was in Melee. Just restore all the knockback, hitbox size, and angle values (and frame speed) of all of her moves from Melee and she's a great character again.
She was perfect in Melee, even if people disliked fighting against her or didn't find her fun to fight against. She was hard for a lot of characters, but that says more about the other characters than Jigglypuff. A lot of character's hitboxes in Melee simply couldn't match up to her Bair disjoint. Fix that and the characters do much better against her. (See: Project M)
Jigglypuff was never the issue in how good she was against other characters in Melee. It was because the other characters weren't good at challenging her in what she was good at... hard spacing and reads that lead into KOs. She was rewarding to play and was only nerfed in Brawl so hard because of fan outcry... (now look at the current Melee metagame and you tell me she's still the best character in the game...)