Well, I suppose that's where we differ in personal philosophies.
I'm always willing to drop what may seem good if I know I can do better.
Then cut any of like the other 30 something characters with inferior movesets, playstyles, and whatnot who were previous playable instead of Jigglypuff. You know, pick the obviously not good ones with less potential, like Luigi, Dr. Mario, Bowser, Link, Young Link, Zelda, Ganondorf, Meta Knight, Lucario, Mewtwo, all of the Pokémon Trainer's Pokémon, Pichu, Roy, Pit, ROB, and heck, probably all of the newcomers confirmed so far in Smash Wii U and 3DS.
I don't think we'll ever see any of those characters top what Jigglypuff was able to accomplish in Melee, whereas with Jigglypuff in Melee, I think we could easily, easily, easily see that level of epic uniqueness, fun, and just engaging style return again in Jigglypuff, because Jigglypuff is probably one of the easiest characters to design and balance. It's so easy (comparably) to do Jigglypuff right that it is hard to see where it went wrong in Brawl.
And also, how do you know Sakurai, you, or anyone else can do better=??? Literally most of the most unique characters are already playable, unless you want just a bunch of empty slates to make up wacky crap (in which you already had that in characters like Fox, Captain Falcon, Ness, Lucas, Luigi, Peach, Bowser, Pit, ROB, Snake, Wario, Marth, Ike, etc. etc. etc, many of which were well done and better than pretty much all potentially new characters).
You sound like you just want to start anew for the hell of it. Quite frankly chopping down the best trees doesn't make the forest any greener. "Moving on" doesn't mean you have to melt away all the past. You can change the previous characters, you know, like how Captain Falcon has gotten several new moves, Luigi has become really unique despite still having several borrowed moves, or how Fox and Falco barely share any moves.
Honestly, I think Jigglypuff's best days could be ahead of us, actually. I have Jigglypuff as my secret top tier character choice, actually.