Hopefully good.

I hope for a rework of certain older characters since ones like Samus could do with an update and for it to closer to Melee in terms of general mechanics. Ideally it'll have rollback netcode but I won't get my hopes up.

And I don't get this idea that they'll just re-release Ultimate on the successor since not only would that not sell anywhere near as much as a fully new game considering how much Ultimate has sold it would also not be a major system seller like a new Smash would be so it would be a bad business decision for Nintendo to use one of their biggest series like that for their next system.

Mario Kart sells more than Smash and it's only had enhanced/DLC port and a RC car spinoff on Switch. It's completely plausible to coast off of Ultimate for an second platform generation. 

If they add a few more fighters and stages and enhanced graphics, it's a 10 million units guarantee. And it could hit 15 million. It would not sell as well as a brand-new Smash, but the cost and development time would be minimal compared to a new game. 

Ultimate on Switch is likely the absolute pinnacle of the series in terms of sales. I would be shocked if a future Smash ever manages more than 20 million units. 

I would only be "happy" with an Ultimate enhanced port if Smash 6 came out on the same platform 2-5 years later. I don't want to wait until 2031 or later for the next Smash. 

But as you said before hat was originally a Wii U game so only a small portion of potential Mario Kart buyers bought it for that. I'd say it'd only be a guarantee to sell that much if the successor isn't backwards compatible and I doubt it won't be and the loss of hardware sales would be notable.

I wouldn't be shocked by that since Ultimate is probably gonna end up selling around 40m so a good sequel should easily go past 20m.

I do agree with not wanting to wait that long though, I wanna see a completely new one by 2026 at the latest.

A smash hit, what else?
...
I'm gonna head out now...

That would be very strange. I mean they did that with MK8 because it came out on the dead system Wii U. There would be no logical reason to re-release Smash Ultimate next-gen when its sold 30+ million on Switch. Of any possible Smash scenario that would seem the least likely.

I mean they could rerelease it with the DLC and a few minor improvements but that wouldn't be next-gen Smash. Ya know. Like that's not what we're talking about for what Smash will be like next-gen. Re-released Ultimate might sell a few million but nobody would consider that to be the Switch 2's version of Smash bros. That'd just be a quick cash grab by Nintendo. Nintendo would still need to make a new Smash for Switch 2 or skip that generation, regardless of any little Ultimate rerelease they do in that scenario.

Would be great if they could use Ultimate as the base for the next game as opposed to working from scratch. Just add new characters, stages, items, etc.

I'm pretty sure Nintendo won't get nearly all the rights for the different characters that Ultimate has back. I expect about 20 cut characters, with a couple new entries from yet unused Nintendo IP and some indie titles (where getting the rights should be easier and cheaper than for AAA characters).

Im a simple man. I just want Isaac from Golden Sun.

Sakurai confirmed Smash 4 to Smash Ultimate involved some reusing of software systems and elements. 

Brawl and Smash 4 both used the Havok physics engine.

Pretty sure the first three Smash games were mostly made from scratch (at least in comparison to each other) and then after Brawl they decided to streamline things.

I totally support reusing a lot of Ultimate's engines for a sequel. I know this isn't engine-related, but I would like a new announcer. Even if Xander Mobus is likely the best Smash announcer, I don't want the same one three times in a row.