I keep seeing people discounting rumors involving "transformations" because Sakurai said there wouldn't be any - but let's not forget that the very same Nintendo Direct showed at least three (Mega Lucario, Mega Charizard X, and Giga Mac - and I assume Giga Bowser and Super Sonic are still in there).
What he meant was transformations triggered by moves. Final Smash transformations are still quite common. Probably obvious to some, but I've seen several replies get this confused already (specifically, a few people refuted the Sick Child leak because of this)