Yerm on 11 March 2017
Sakurai stated that his reason for not having a story mode is SSB4 was because when Brawl released, people quickly dumped the game and uploaded all the cutscenes online, which he felt ruined the experience. So instead he made a bunch of cinematic trailers used to reveal newcomers and generate hype. And that worked a bit TOO well. They were able to create a successful advertising campaign without increasing the cost of production, and people lost their minds over the trailers.
Plus, Smash Bros as a side-scrolling platformer feels weird now, looking back on it. (just a thought)
I think a few new characters, new stages, and possibly a better use of amiibo would be enough
