In my opinion. I think the best possible thing to do would be to never have another Smash title and just keep updating Ultimate with crazy ridiculous characters. I do not know how viable this is for Nintendo but it would be what I want.

Smash doesn't need a new title. However, it will need more characters eventually. Where's Waluigi? Where's Crash? Where's Mister Cheef? The potential is endless. Nintendo are sitting on a gold mine. The problem is Sakurai is the only one who can pull it off. I'm afraid he's just sick of working with Smash and who blames him.