I think I've said this before but personally, while this obviously won't happen for a lot of reasons, I would want a full MVC style roster that goes for picks which are more out there but unique and surprising, "cutting Peach to add Mona" style choices. Ultimate is already going to be playable on the Switch successor and has every character which I think makes the idea of really going out there with the roster and replacing a bunch of characters who seem obvious a bit more palatable, I think that would be the most interesting option and result in a healthy game with a lot of potential for diverse playstyles
Again though this isn't going to happen for a million reasons, Smash is one of Nintendo's biggest mainstream IPs and is also a vessel for advertising, and I'm sure Sakurai wouldn't want to go that route either.
I don't think this is a very accurate interpretation of how Capcom did rosters for MVC. (Or a good idea in general tbh.)
MVC was originally very X-Men focused with the shift from 2 to 3 being about expanding the variety. It wasn't a literal case of "Oh, cut Cyclops for Taskmaster," specifically or anything like that. And even then, most of the additions were significant franchises in the last generation on the Capcom side and major or soon to be major properties on the Marvel side.
Infinite completely axing the X-Men wasn't by Capcom 's choice either. Their hands were tied due to Disney/Marvel.
You can't pull an MVCI with Smash and expect it to go over well. Some faces
are mandatory and it's not like Nintendo has someone else to answer to in regard to their own IP.
Either way, Smash has
already been doing the wacky, out there, pulls since it's inception. It's no different from MVC in that regard. Not everyone is going to be a Shuma Gorath or G&W style of pick, most characters aren't.
I
would like to see Mona and other "lesser" or out there characters (heck, I'm a Shokora supporter) but specifically targeting certain characters people expect to see and replacing them with smaller names just because isn't the way to go about it.