Can we agree that Crash, Waluigi, Geno would pretty much be the next big 3 of the smash community during the next smash game?
It's...immensely hard to say. Waluigi is the only one I'm confident will have
that much of a following, since he has virtually nothing standing in his way that can't be overcome next time.
The reality of the situation is that any semblance of a "Big 3" or "Big 4" or what have you only happened naturally during Smash 4. Any attempt to claim such a thing happened during Ultimate is revising history a bit.
Back during Smash 4 there were several proposed newcomers that were virtually
unanimously wanted and expected by the community. These were Mewtwo returning, and the additions of Mega Man, Ridley, King K. Rool, Palutena, and Little Mac. At least here on Smashboards, anyway. Gamefaqs was
mostly on board with that list too. Now of course, there were other
categories that were fairly universal, but the exact choice wasn't. Most expected a Fire Emblem character, but there was a split between Chrom joining and Roy returning. Mario newcomers were a hot topic, but it was a three-way split between Toad, Bowser Jr., and "the four we have are all we need." Most expected a retro newcomer, and Takamaru was the most common pick, but it wasn't unanimous. Shulk and Isaac were both common requests but were often seen as mutually exclusive.
But Mewtwo, Mega Man, Ridley, King K. Rool, Palutena, and Little Mac? Those were truly unanimous. If you posted a prediction roster and even one of those characters was missing, there would 100% be heavy scrutiny and debate. And then all but Ridley and K. Rool got into Smash 4 (albeit with Mewtwo being DLC).
That's why I always advised against trying to recreate that. Many tried to frame Ridley, K. Rool, and Banjo as the "Big 3," but in truth, there was
literally never a point where those three, specifically, were the three most wanted characters. By the time Banjo was seen as a possibility during the ballot, Ridley had long since been written off by most of
his own fanbase as impossible, based on what happened in Smash 4. And since Ridley was the first post-Inkling newcomer revealed, there wasn't any time for that specific trio to really BE the "Big 3."
The other thing is that when the unanimous Smash 4 requests were, well, unanimous, the fanbase was working under much more restrictive guidelines. Third party requests were far less common and had to have very strong ties to Nintendo. Characters had to come from combat-oriented series due to Animal Crossing and Nintendogs being barred from Brawl. Even brand new Nintendo series for the roster had a hard time getting a unanimous following because prior to Smash 4, very few Miscellaneous new series were added, especially if they weren't retro or third party (just Fire Emblem in Melee and Pikmin and WarioWare in Brawl, but even Wario had the Mario connection). Smash 4's opening of many doors (Villager and Wii Fit Trainer, lots of new miscellaneous Nintendo franchises, and opening the door more for third parties) made it so truly unanimous newcomer sets would likely NEVER happen again.
Crash and Geno, respectively, would face division due to there being other Microsoft (lol) and Square-Enix characters seen as "competition." And apprehension due to Geno's unique rights issues would only further muddy things.
At most, I can see Waluigi filling a similar place as Inkling, Isabelle, and an Alola Pokémon during Ultimate's pre-release, where they were seen as among the most likely characters. But I don't see the rise of a unanimous "Big [Collective]" ever again.