I was thinking about what the next Smash Bros game would be like and how they can improve it. 

I think Ultimate is pretty dang perfect, outside of online features.

If they were to create a Smash Bros. Ultimate: Switch 2 Version and improve the online features (rankings, stats, etc...), accessibility (easier and more match-making options with friends), minor graphical and performance upgrades, I think that would be a home run! Maybe add a character here and there... I think that's all I'd really need out of a "new" Smash game. Maybe add some more single player content? (although I don't play much single player when playing Smash)

What do you guys want to see from the next Smash game?

If they try and make a brand new smash bros for Switch 2 they will run into the same problem as MK.

I'm not a big smash bros fan but MK8 for me personally was the perfected end point of the standard MK formula. It was a game almost impossible to build a successor for. So MKW they had to try something different and for me it's just not as good. Smash Bros may be in a similar place.

Ultimate has such a ridiculous amount of content, like mk8d, that they just won't be able to surpass it in that aspect, and graphics leap alone won't be big enough to justify the new game. So they have to make big changes to the series instead.

With MK World that was openworld and 24 players, what the big changes to smash bros would be I don't know.

Maybe they will be more successful in revolutionising the smash series but an updated ultimate is probably a safer bet.

Though if they go that route hopefully it's more than just a resolution bump and camera putting your face at the bottom of the screen.

In order for people to accept a smaller roster, I think they should add a new general mechanic to spice up the gameplay and differentiate it from all past iterations. For example, Street Fighter has a lot of returning characters and they mostly retain the same moveset but SFIV had Focus Attacks, V had V-trigger, VI has Drive Impact which means every game plays differently.

I basicly only care about getting a Subspace Emissary V2 (and some unlikely character additions). Otherwise I'm indifferent to whether they continue Ultimate or start a new one. I do think Ultimate has some rarely talked about flaws with UI, spirits, etc. so I wouldn't mind losing some characters for them to take another stab at it.

Though I suppose they could also do what Ultimate did with Smash 4 and keep the bones of the game, but otherwise make it a new entry. That might be the best solution even if it is the third game in a row to be quite similar then.

I did really enjoy Subspace Emissary! Agreed that was such a cool story mode...I wish they would do something like that again

I would gladly take a "Smash Ultima Deluxe Switch 2" version, if it includes all the previous DLC, enhancements like 120fps or 4k and some new content like new fighters, stages, modes, etc. I think Smash Ultimate is a great game and I can't think of many things that could be added or improved. 

If Super Smash Bros. Ultimate Switch 2 Edition is the Smash for Switch 2, I have some wishes
-At least 5 more fighters and 5 more stages
-Subspace Emissary Remake or "sequel" added as an extra adventure mode
-Smash Run
-Mouse controls (duh)
Simply adding in a few fighters and mouse controls is not enough. Smash is an event for many of us and if we have to wait until the 2030s for a new Smash that could be agonizing.
Also, they should add Super Smash Bros., Super Smash Bros. Melee, and Super Smash Bros. Brawl to NSO. Yes, Wii should be added to the Expansion Pack 2028 or sooner.
All of that would be a big celebration of Smash and tide us over until the next system and 2030s.
The next Smash (whenever it is) is going to need to bring the roster down to 80 or below. Maybe even in the 30s if a lot of characters are significantly changed.

No.

Make it a deluxe version with DLC included and a couple of new stages included - kinda like MK8 deluxe was - and id be fine with it.

It seems like we might lose either way given Nintendo's pricing and such. If it's a Deluxe version that isn't a Switch 2 upgrade, it will likely be sold at full price by itself unless Nintendo makes an exception with an upgrade purchase.

If it is a Switch 2 version, the DLC will surely still cost money. Breath of the Wild's DLC is not included for free in the Switch 2 upgrade.