Most of Incineroar's playerbase plays him for the moveset, not the Pokemon. Combine this with how his moveset is 100% human, and Sakurai might as well have given us a Pro Wrestling rep instead.
That's what feels so
off about the moveset: It feels less like it was designed around the character and more like it was pre-built some time prior and then pasted on. There's nothing involving any character-specific abilities, no fire belt, no outright heel tactics, nothing hinting toward the persona just being an act, none of it. You got a Fire/Dark type whose moveset feels like that of a pure Fighting type, something any number of wrestler characters could've also done.
And when there were so many other options from Gen 7 that, arguably, had the potential to do some
very unique things, no wonder it still feels like such a hollow decision. It feels like in this case, one fandom was
used in order to appeal to a completely different one, as if they didn't matter and were no more than a tool to be exploited and then cast aside once they were no longer convenient. Which just so happened to play right into the hands of some...not-so-pleasant facets of the Smash community.
But the strangest part is how much of an anomaly it is. We've seen several cases where characters were chosen specifically for uniqueness, for what new things they could bring. Ike got the inside track because he could be a cross between a sword user and a heavyweight when Smash didn't have many of the former yet, then his moveset pulled a
lot of moves and animations straight from his game. Robin got the all clear thanks to being a spellsword with a hybrid arsenal no one else could match, all while using a weapon durability mechanic straight out of Fire Emblem. Even recently, Sakurai has outright said the reason Piranha Plant got a chance was how it can do things that literally no other fighter is capable of, and that's on top of all the moves that are directly inspired by different subspecies across various Mario games! So to have a character in the midst of all that be chosen seemingly just to pay lip service to an idea that isn't even part of its home series, and outright
rejecting at least one other character with unique abilities in the process? It's enough to wonder if more went on behind the scenes than we've officially heard.
Not that it's directly pertinent to us, anyway. Our biggest problem was, and still is, timing...
I think Incineroar appealed to Pokemon fans, but not hardcore Smash fans.
From what I remember, Incineroar was fairly popular (maybe not as popular as Primarina) once SuMo released and people realized it wasn't a fighting type. Decidueye was actually the one who struggled, but its popularity among Smash fans made people think it was popular.
Actually, among the Western fanbase at least, Decidueye really
is extremely popular. It's more subdued over in Japan, where apparently Primarina is a bigger deal, but there's definitely a following. Granted, a lot of speculators wrote Decidueye in for other reasons (usually the "we need a Grass starter to complete the set" kind) and then worked backwards and used the Western popularity to justify it, so some of it got masked. Incineroar went from
very divisive when the art leaks happened, to still fairly divisive after the official reveal canned the Fire/Fighting fears, and there're still pretty mixed opinions even now from what I've seen.
Not that popularity is as crucial or objective as the speculation community treats it as half the time, anyway. I've seen it used too often to dismiss ideas and shun people just for going against the bandwagon.