Buzzwole's way to big, like even sized down his hit box would still bigger than Ganondorf's hit box vertically and a full arm lengths punch (amusing no theatrics are involved) would be longer than most of the sword fighters.
I don't think well be seeing a Gen VII in the roster this time round. But Decidueye makes since in terms of size, movement, and moveset. Mimikyu has a decent following and could have a decent moveset as well. The rest of Gen VII I don't see happening, despite UB popularity or even Tsareena, Lurantis, and Salazzle's popularity.
Also I wouldn't mind have a Warioware rep to actually rep Warioware rather than the ball of weirdness known as Wario.