No. She has more than "a" weakness. That is her biggest weakness, and it always has been. Her other weaknesses are more apparent in Project M than they are in Melee, mainly her combo-food status. Just about every character has a high-percent juggle on her in Project M, it has been like this since I've used her in 3.02 which has been the past 6-7 months.
She also has another very notable flaw, and that is her inability to get out from above characters which can juggle her. She has no way to jump up and drop down really fast, and neither does she have a move that has high priority under her hurtbox. I can only think of one move that has a hitbox below her, and it's laggy and leaves her foot hurtbox completely exposed, air dodging is highly compromising in Melee and Project M. While it might work in some situations, it is not reliable.
With a laggy recovery, the fact that she gets combo'd by just about every character in this game very easily and for a lot of damage, and on top of that, an inability to get out from a juggle reliably like a lot of characters can, outweigh her neutral game's advantages severely.
I won't take it away from her; she's a great edge guarder and even more so now that everyone's recoveries are a lot riskier and more predictable. Her grab game is also very good compared to the rest of the cast, and her ability to poke you from afar with needles and sometimes gimp you with them is also a very strong asset of hers.
I think that at the very least, a little reduction in landing lag from up-b is a reasonable change. As it stands, it is EXTREMELY laggy. That's my opinion after maining her exclusively for consecutive months.