Aside from a criminally high amount of veterans being as of now up in the air (Ness and Lucas' omission is particularly frustrating to me), I'm hard-pressed to come up with anything terribly wrong with what's been shown as of yet. The higher ending lag on aerials, edgeguarding changes, and kill power issues I've heard tossed about seem like things that I'd have to experience firsthand to take issue with, and none of them seem like dealbreakers in the long run, especially given how much the gameplay already changed between each of the previous installments. As far as complaints about the final game's content, I would say that it does seem like the 3DS version is getting a bunch of gimmicky stages compared to the Wii U, but we haven't seen all of them yet, and since it's on a handheld and I don't foresee playing it multiplayer as much as the Wii U version, that might actually be for the better. The roster as of yet is fantastic, if incomplete (hopefully Meta Knight's veteran reveal today is a sign of more to come), a lot of the new items and stages look really promising, Smash Run looks amazing, and I like that the gameplay seems to be taking some pages from Smash 64 (again, I'd have to play it firsthand to know for sure...).