Just kinda thought that "bandwagon" was the right term, though I didn't particularly mean it like that. But I hope you can see what I'm getting at when I talk about the same characters being repeat ad nauseum in pretty much every single fan roster out there. And sure, maybe it's something one would expect if a character really is just that popular, though if I'm being honest, I feel like the only reason someone like Waluigi is on a lot of people's radar is simply because they think "it's his turn". They're pretty much expecting a new Mario character with every Smash installment (and granted, Mario is Nintendo's flagship franchise), and he's just the next in line. While I wouldn't doubt that Waluigi has his share of genuine fans (especially given his prominence in memes), let's be real: hypothetically, if Smash was forced to have only 5 Mario characters (and let's be generous and discount anyone from the Donkey Kong, Yoshi, and Wario series), do you think Waluigi would come anywhere close to making it in? Is it any surprise why Waluigi isn't already in Smash now? Seems like the same thing with Crash, really. We got Mario, we got Sonic, we got Pac-Man, Crash just seems like the next major "mascot" character (didn't particularly help that a lot of early Playstation ads made him come across as their mascot, when he was really just a third party character all along).
But what do I know? Honestly, I completely wrote off Banjo&Kazooie due to the whole Rare mishap, even when it looked like Microsoft was growing friendlier with Nintendo, and I've long assumed Sora would just be one big legal nightmare (in fact, I'm still somewhat wary about Disney having their grubby hands in Smash).
Some months back, I actually did sit down and try to recall every character in Smash offhand. It actually helps a lot if you can separate characters by which installment they debuted and (not accounting for Echoes) which number was assigned to the last character of a particular installment (ex. Jigglypuff is #12, Mr. Game&Watch is #26, etc.). With that said, I did end up remembering all of them...... except Wii Fit Trainer. I almost forgot about Pac-Man, too (Smash4 in general is where I really started to get tripped up, though I guess it doesn't help that those two are stand-alone Fighters from their respective series.... in contrast, it's somewhat easy to keep in mind that there're 8 Fire Emblem characters).
As for whether I'd care if they got cut...... well, I'm of the camp who wishes to avoid all cuts moving forward. But as for those two in particular, regardless of a failure on my part to remember them, I can nevertheless acknowledge how important a character like Pac-Man is to gaming, and I'm sure Wii Fit represented something to the massive market of Wii casuals back in the day, so I doubt I'd be happy even if they were literally the only characters to be cut.