My logic was a little flawed with Sonic and Mega Man I'll admit, I probably should've just grouped them with Banjo as being highly requested for a while. But Sonic was added in after the game got delayed due to fan demand, and while Mega Man saw a bunch of support during the Brawl days, it wasn't until Smash 4 when he finally got in. I feel Crash will experience a similar fate, sort of like Isabelle, K. Rool and Chrom in Smash 4.
I'm not arguing that Crash shouldn't be in Smash. My main point against him was that I don't think he's requested enough or has been requested long enough to make it into Ultimate. Next game? Easy frontrunner. But for right now, I don't see it happening due to major support for him not starting until after Smash Ultimate was first announced. Crash has done a good job staying relevant these past few years, but even so a character that's seen as such a big request like him would most certainly be revealed at E3 or the Game Awards. It's possible they wait until December to reveal him but it's still not super likely. But of course Crash is gonna be more recognized than any Tekken character by Nintendo fans, Tekken isn't on the Switch and has only had 3 games prior, two of which were handheld games, meanwhile Crash has received a remastered collection, racing game and new entry over the past few years, while always being a speculated character. At the end of the day, Nintendo wants to sell the pass, so they're gonna put their biggest, farthest reaching characters in the middle of the pass. For Fighter Pass 1 it was Hero and Banjo, and for Fighter Pass 2 it was Steve and Sephiroth. It makes no sense for them to end on a big character from a financial standpoint nor have they done it before, which is the biggest thing against Crash atm. And I wasn't saying Crash wasn't iconic. I'm saying that without the Nintendo rivalry, he didn't impact much as far as gaming as a whole. Recognizable sure, but he's a $50 million Banjo as far as I can tell. A rival to Mario sure, but a rival that they basically gave up on after the PS1. He's the most noteworthy unimpactful on gaming third party character I can think of.
My main argument though was against third parties that don't have much in terms of leaving an impact on gaming. They may be known, but most third parties playable in Smash tend to be from series often revered as the best in their genre, and if they're not they're characters that have been highly requested for a while. I don't get your section on Castlevania at all considering it's part of the name of an entire genre right alongside Metroid, which has inspired many other games to be made.
I'd be curious to hear who you consider fits the criteria though, cause there's definitely plenty of options (deconfirmed or not)
To be clear, I think it's increasingly likely that Crash unfortunately misses this boat, but I don't agree with a few of your points:
1.
Fighter's Pass 2's "Hype Curve" - I find some of the Fighter's Pass 2 theory crafting in terms of the big reveals a little bit less convincing than a more obvious pattern with Pass 1, and I think that's made some people lean too far into Pass 2 emulating a similar curve of hype/major series. But the reality is that's just not the case and largely hasn't been since Min Min made her debut. Joker may not have been the biggest character in Pass 1, but he was very clearly starting off the Pass with a massive bang that declared Ultimate was playing by a whole new set of rules in the DLC. Min Min, and I mean this with no offense to her or ARMS, is incredibly far from being this type of character. In fact, I'd go as far as to say that she's the smallest character of this Pass with how requested XC2 had become. Sure, Steve was then huge and Sephiroth was big, but then we saw another fall in the crossover only for it to rebound to Kazuya, who I think absolutely matches Sephiroth in terms of appeal.
The arc isn't there and people can point to a financial incentive all they want, but Min Min already kind of throws that out the window. They didn't start from a particularly high note to get people super excited and buying into the Pass immediately. A well crafted and well received character? Sure. A traditionally hype pick that sets a tone in the same way Joker did? Not even close. They could have front loaded Steve, Sephiroth, and Kazuya, but they very clearly didn't and even broke up their big third party crossovers with another first party of a smaller, albeit somewhat requested, scale.
I think it's very easy to forget that Smash 4 didn't technically end on a "less hype" moment, it ended on Bayonetta, an incredibly popular character that people thought was impossible. I know a bunch of very angry fans either hyper fixated on Corrin or have spent the past 5 years downplaying Bayonetta's accomplishment, but I think it's worth noting that while Bayonetta was not the "biggest character", she was still a kind of crazy third party inclusion. So Smash 4 DLC and by extension Smash 4 did not end on a "low note" as much as people may try and argue the point, and I think it's worth considering they decided this next character to be the
final character of Smash Ultimate when they decided this Pass it seems. People can obsess over Fighter's Pass 1 or Base Roster not ending on the most hype inclusion... but this is also an entirely unique context that I think warrants a little more curiosity and the only point of comparison that rings true for me is Smash 4 ending with Bayonetta.
2.
Crash Has the Type of Influence You're Claiming is Needed - I think it's kind of easy to set aside Crash when funnily enough I think the series actually largely took Mario into 3D more than Mario himself did. And by that, I mean that Crash wasl still a fundamentally level based game about getting to the goal and collecting things along the way whereas Mario helped originate the collectathon. Crash offered a different option to developers that was still much more inherently focused on getting to an objective at the end of the level one level at a time and pretty much defined how you would approach that concept and was seen in other platformers during the late 90s and early 2000s. And like it's easy to take for granted nowadays, but back in the mid 90s, that kind of successful 3D platformer that early on in 96 had an influence.
Beyond that, Crash was a defining mascot of the PS1. I shouldn't really have to say more in how influential that was. The PS1 put Sony on the map and absolutely demolished the Nintendo 64 and Sega Saturn at the time. Crash was as to PS1 as Mario was to Nintendo as Sonic was to Sega. He didn't get to enjoy that success beyond that era as he was a third party, but for a time he was an industry defining mascot that Sony used in lots of things and was an actually serious competitor to Mario in the 90s.
Crash as an IP has sold over 50 million copies of titles, which puts him actually in the big leagues (for the record, he's only below Final Fantasy, Dragon Quest, Sonic, Minecraft and is basically matching Tekken for franchise sales) and N'Sane Trilogy alone sold over 10 million copies and is one of the highest selling third party releases on Switch. I think there's more than enough history, legacy, and popularity even as just a recognizable gaming icon to warrant him fitting in with the criteria you've listed.
3.
Third Party Criteria/Castlevania - My point was to show that there are options in Smash that don't exactly fit your criteria. Trying to ram Persona and King of Fighters/Fatal Fury into the "Sakurai Bias" column feels really forced when
Nintendo made that decision and also discredits the individual legacies of both of those franchises despite them actually being really quite influential and less overtly successful. They may not have the biggest legacies, but they have a legacy, are notable franchises in their own right, and have plenty of reason to be included beyond Sakurai having a personal interest in them. Sure, Smash has included a lot of legendary and genre defining franchises and will continue to do... but they are reaching a point where they have to dig a little deeper for options. Which is to say, for Japanese third parties with sales over 30 million copies, there's basically Resident Evil, Monster Hunter, Kingdom Hearts, and Dark Souls. At some point, they are going to be choosing less inherently successful and defining franchises because they've done such a good job at including so many. And that's not to knock those franchises, but just, they aren't as financially successful as those already in.
As for Castlevania, it defines a very narrow specific sub-genre of games with Metroid that was arguably the bigger influencer, but it is ultimately a 2D action platformer, of which tons came of the 80s and 90s. I'm not saying Castlevania wasn't of high quality, influential in some ways, or beloved, but rather it was just a generally successful IP in the land of successful 2D platforming IPs. Not a knock on the franchise, but rather an acknowledgement that it is the smaller side of the massive IPs in this game already close to the likes of Persona and SNK rather than Sonic, Final Fantasy, and Minecraft.
I don't really agree with your criteria, but a short list of options would be: Arle from Puyo Puyo, Kunio-kun from River City, Dragonborn from Skyrim, any Dark Souls character, yes Crash Bandicoot, Dante from Devil May Cry, Sora from Kingdom Hearts, Adol Christian from Ys, Phoenix Wright because he's been a defining figure of visual novels (Ayumi if you wanna go old school and Nintendo), Master Chief from Halo, and Doomguy from Doom all fit the bill and tons more for that matter.