I'm kind of worried about Mewtwo's representation if it's in. Even beyond it potentially being represented by its horrid mega forms (and they are very horrid, but I don't see it being too likely at this point, at least, not out of a FS transformation), I really hope they don't give Mewtwo its new feminine voice, and I really don't see them not.
It's not that I dislike the voice, I'd just rather Mewtwo not remind me of the film's weak and canonically nonsensical new Mewtwo. When I want Mewtwo, I want Mewtwo as it was. The more I think on it, the more I realize how much Mewtwo missing Brawl made these negative possibilities more likely. Had Mewtwo appeared in Brawl, there would have been precedent to keep Mewtwo as it was, but with a non-appearance separating it, there's more room to get away with changes like that. Not happy about it.
Maybe in card form in the TCG game? I don't remember.