Perhaps, but do remember that even with a new forme, it's still Mewtwo overall, not a brand-new pokemon. I'd also like to add that Sakurai likes representing the Pokemon series overall rather than what's recent, which leads me to believe that Mewtwo will be represented in the forme he's best known in, which is his original look. But hey, I might be wrong, but I do feel as if the Eevee family is important enough to the franchise to represent in Smash, and having pretty much nothing from the Eevee family, not even a pokeball pokemon, is kind of insulting.