Honestly, I’d be in favor of a reboot. I think it opens up many new doors and possibilities.
At this point, Ultimate feels like the conclusion to Sakurai’s work and while many will claim that we can only go up, I don’t really see how we can. Most of the big fan requests have been met, and the others just seem far fetched at this point. We have a roster that will be comprised of 75+ characters, you can’t really go much further than that without angering the Smash community as you pull from non-Nintendo 3rd party, or the millionth FE or Pokémon character. Unless Sakurai steps down I doubt Kirby or Zelda will ever get another rep, or more classic franchises like Golden Sun will ever make it in, so where could this series potentially go.
I want to see something new from Smash now, a restart that fixes up many of the moveset issues and character inaccuracies of the previous titles. Maybe one that’ll cut the fat of the roster and update it to be more inline with the times or have characters that are important to the series as a whole rather than important/new at the time of a Smash release. Characters like Shiek, Young Link, Corrin, Doctor Mario, Pichu, Roy, Dark Pit, etc.. have like no place at this point and feel there because Smash added them at one point, rather than their series or fandom still supporting them.
As for the idea that the general public will go against the decision, will they really? It’s going to be a good 10 years before a new title it seems, that’s plenty of time to find a whole new audience and for previous players to forget. Most will just buy because Smash anyway as long as the game is good.
I believe there is a lingering lust for a new direction to Smash with quite a few asking if the series is stagnant at the moment. I think many believed the reboot was actually going to be Ultimate. The series is roughly 20 years old now and has yet to really make a huge change up. Every fighter has a nearly identical moveset to the previous title with only one move change here or there, most likely due to technical issues. It’s fine for now as this feels like a celebration with Ultimate, but the next title won’t have that to keep everything afloat. Everyone is Here has been done now, now your just throwing the same party but inviting 10 more people. It won’t have the same impact the second time around. I guess I’d rather have Smash move on and create a new direction to celebrate rather than being stuck in an endless loop.