Gonna bite on this balance topic:
Smash has a lot of variables to consider that aren't present in other fighting games that makes it harder to balance:
First, and most strikingly:
It balances across two completely polarized modes of play. Other fighting games do not have to balance for the 4 player FFA insanity that is this game for most players. How do you even balance it? Not even competitive players have really looked at balance in a FFA setting (just meme level arguments about Ganondorf and Shulk, and maybe Olimar and Sheik being bad) and no other game (except from the broken mess that is PSABR) has tried this at this degree. Imagine being Bandai-Namco and trying to balance this game, with practically no game playing like it.
Second:
The game has a knockback system and increased freedom with aerial movement. You have to account for base knockback, knockback scaling, the angle a move sends you (and DI associated with it), horizontal and vertical recoveries, falling speed, horizontal aerial mobility and jump height, along with traditional fighting game attributes such as frame data, damage, range and mobility. This is only scraping the surface as there's a variety of character and stage specific mechanics they also have to consider.
Finally:
Sakurai makes characters that have bat-**** crazy designs. He literally balances on "extremes" with characters having some polarizing strengths and polarizing weaknesses. The characters that have one or the other (which is usually due to FFA being priority and not translating well with 1v1) turn out broken on either side of the spectrum. Regardless of what you feel about this style (I don't like it, but some people think it keeps everyone from being Mario lmao), it makes balancing really difficult because Sakurai has to avoid either side of broken (especially on the overpowered side).
I think balancing a cast beyond 75 or so characters is going to be rough, so I don't know what will happen if it gets to that point with this game. Cuts will definitely need to be considered after this Smash title, but could happen with Smash Switch. It all depends on how much time they have. Smash 4 without patches actually has a large number of really poorly balanced characters (almost to the degree of Brawl), so I do have concerns even if Smash 3DS isn't going to be a time succubus this time around.
Rough, but not impossible. Another thing that comes along with Smash besides newcomers and cuts, are balance patches.
A little tweaking here and there after the final product has been released to the public.
I just don’t understand what you think this game will be. All of us are in the dark here.
A roster reset that drastically cuts the roster, while it may improve quality of the character, would enrage so many people. Especially if characters they liked were removed.
Having no cuts, and a few, 5-8 newcomers, does not make a new game. It’d be marketed as one, but be a deluxe port. That’s cheap. It’s a cop out. That too would enrage people.
I know at some point Smash will have to take a hit in the roster. I don’t see Smash V as being that time. Especially with so many potential newcomers coming down the pipeline.
Would it be difficult? Yes, I agree. But it’s not impossible. And if we know anything about Masahiro Sakurai is; he pushes himself to his breaking point, and he loves cramming as much content as he can into these games.