I agree that unless we get Heavy Technological Advancements, Trying to build a New Smash game with Different foundations is gonna be Impossible without Heavy Sacrifices.
The thing is that There's not much of a reason to change the Foundation at the current Moment, especially since there's still not really a Real, Threatening Competitor to Smash's Gameplay Formula at the moment. We have to see what WB does with their game, but otherwise the other Smash-Like games can't really compare I would say
Like I've said, the thing with Ultimate is that the game is very Fined tuned, and most Importantly, the Balance is very Fine tuned. Now yes the Balance isn't Perfect, and there are still some Degenerate Balancing Decisions in some people's Eyes, but overall it is in a very good spot, especially when you compare it to Previous games where Both the Universal Gameplay Elements and Character Balance were a Mess and resulted in some of the Most Broken Characters in Fighting game history.
Ultimate wasn't just about Bringing everything back, but it was also about Fine tuning what exactly they brought back, including the Characters/Veterans themselves in terms of Expressions, Animations, Balance, and Game plans, The actual Gameplay Elements of the game, The Stages, even some of the modes, etc.
Unlike Previous Smash games, I don't think Ultimate really needs a Shake up in terms of changing the Elements unlike Previous Smash games, so I think it can focus on Expanding the Game that's already there with Quality of Life Changes and Additions to Content. Gameplay Additions would be Nice, but I actually don't think is needed.
Nintendo does love adding Gameplay Elements to Sequels or Expansions, but as Splatoon 3 and BOTW2 is showing (Even if we don't have that much footage of either, especially the latter), They especially now are willing to keep to what previous Games have established. I think this is more true in Today's Gaming Industry. Development Costs have Skyrocketed from the Past days, and it's only gonna keep Rising and Rising, along with the Expectations of what games need these days. Sakurai and Harada I believed talked about this very thing on Harada's Bar
I know Pokemon Comparisons have been made, and there is some truth to arguments made about it, but I think there is different variables in Smash and Pokemon's Case
-Sword and Shield was really the First Mainline Console Pokemon game I can think of, so the Transition to that form of Development is something to consider. The Sacrifices of Sword and Shield were painful, but with the task already of having to have a New Foundation, it was needed. Going into the Next Smash, there's not really a "Necessary reason" to have to change the Formula or Developed Base as of now
I also don't see the Next Console after the Switch being such a High Upgrade over the Switch that it would require Restructuring the Base Assets of Smash Ultimate. It's not like we going to Xbox Series X, PS5, or PC levels of Power I would think.
-While Sword and Shield did sell Well to the Casuals, managing to top 20 Million, I don't think that means that Nintendo can just get away with anything
Looking at the Sales of Past games, and the Sales of Sword and Shield, it is obvious the Hardcore Crowd did have an effect on the Sales of Sword and Shield. Pokemon games on the 3DS were, besides Mario Kart, the Highest Selling games. Outsold Smash 3DS and Animal Crossing New Leaf. Now Sword and Shield got beat by Smash Ultimate, BOTW, and New Horizons. Granted BOTW and Smash are older games, but Pokemon Sun and Moon was able to beat Smash 3DS despite being out for less amount of Time, and there's no Excuse with New Horizons
It's also worth noting that Sword and Shield is likely a lot of People's First Pokemon Game. This is the First Mainline Pokemon Game on a Console like System. People that don't pay Attention to Handhelds might not have Played Pokemon before, but might have had this chance now.
-I really do think that the Characters of Smash matter more than the Pokemon in Pokemon. For one, Since there's much less characters (Playable) in Smash than in Pokemon, the Cutting of one character in Smash is gonna mean more than a Cutting of One Pokemon. The Characters in Smash also mean much more to the Gameplay of Smash than Specific Pokemon do to the Pokemon Experience I Imagine. The Characters in Smash more change up how you Approach the Gameplay than any Individual Pokemon.
Pokemon can introduce Completely new Pokemon to the game and such. The thing is that Smash is working with Already Established characters of their own, so when you have a Scenario where you're Cuttings someone like Snake, that's potential audience that you just lost. The Crossover over Nature of Smash is the biggest reason for it's Success, and all the Fanbases that Crossover.
Going by this logic, I am gonna try to outline who would likely be the main picks for each company going forward. In terms of new companies like Activision or Tecmo their big picks (Crash, Hayabusa) are also pretty solid fan requests in their own right so its kinda moot.
Konami: Aluacard is king. He is very popular and almost made it in Ultimate over the Belmonts. If we get someone, it would likely be him. Bomberman is a solid fan request but I would bet on Alucard.
Sega: This one is hard because you have a few smaller ring franchises in the grand scheme of things like Puyo and to a lesser extent Yakuza. I would say that SMT and Phantasy Star both make a lot of sense. Phantasy Star Online still rakes in money and the series has a strong legacy, so I would go with that if I had to guess. Either someone like Alis from Phantasy Star or Eggman. If you count Atlus alone, do something like Demi Fiend.
Capcom: It's Dante. RE and MH are both huge, but Sakurai nodded to the Dante demand. DMC is big enough and he has the fan demand. The Capcom crown is his for the taking.
Bamco: Lloyd. Tales is one of their biggest series, and he is a fan favorite. Similar to Dante he is in a good spot.
Microsoft: Chief. Yes Dovakhin and Doomguy are big, but Chief is massive. Halo legit is the mascot of Microsoft, if we get another Microsoft rep I would say Chief takes it even if I could see both Bethesda reps making it in.
SNK: Kyo most likely, he is probably their second biggest character.
Disney: Look, KH is weird and we wont end up with a Disney character themselves, so a second KH rep by default.
To be honest, the only real exception I could see is an Indie rep, but that crown is Undertale's for the taking imo and Undertale and Deltarune are massive.
I'll mention couple of my takes
Sega: Another Sonic Character is definitely the King here, no Questions asked. I acknowledge that Puyo Puyo, Yakuza, SMT, and Phantasy start are Franchises, and SMTV could be the game that boost up it's Franchise like what Persona 5 did, but those franchises aren't the ones that are getting Movies and Netflix Shows, and despite Sonic's Games being in inconsistent Quality, they continue to sell reasonably well and is among the Main pillars of Sega's Revenue. Characters like Eggman (More recently), Tails, Shadow, & Knuckles are also among the most requested characters
Capcom: I think Monster Hunter is done in terms of getting a Fighter, I do believe that Capcom wants the Monster to shine through the most rather than the Hunter. However I think they could try to Attempt RE again for the Next game
If they aren't already in the process and/or Finished with that, and if they succeed in that, I think RE would be the Choice here, not Dante
Also I'm gonna be perfectly Honest, I'm unsure if they would manage to Make Dante in the Base game if the Next Smash game. If there's one character I think Absolutely has to be DLC due to Developmental reasons, it would be Dante. I don't think they would go the Sora route and Simplify him for Smash, but go in the Complete Opposite Direction and make him the Complex Beast he is in DMC.
What I honestly could see happening is if they must have a DMC Character in Base, they would go with Nero. He's the Forefront of DMCV, The Highest Selling DMC Game, he is a Popular character, and His moveset would definitly have Uniqueness, but would also be Simple enough to Implement and Balance. It also would be more Fresh since Unlike Dante, Nero hasn't been in a Fighting game before. They could then Save Dante and Vergil for DLC once they already Roped in the DMC Fanbase
Namco: I could see Lloyd, but I also think Yuri, and now recently, Alphen and what's her Name (I forgot) from Tales of Arise could be the Characters for Tales of. Tales of Arise is looking to be the game that brings Tales of to the Mainstream more than any other game
Even then, I could see Agumon because Digimon is Digimon after all.
SNK: I honestly could see a Situation where Iori gets in over Kyo, because People love Iori and think he is Brillant, including Sakurai himself.
Disney: I still do think Mickey Mouse could honestly be a thing, and might actually have been a Stipulation for having Sora in the game, because I think Disney themselves know Mickey going against Mario would be a Big deal, and Video Games is the Biggest Entertainment market over Flim and stuff.