As someone who had to "fight" lots of part of the smash Community about everything Square-Enix related for years since I joined this website, whenever it was Cloud, Dragon Quest and nowadays clamoring for Sora. Or even that Sephiroth was one of the most influencial Vilain in all of the JRPG genre back when he was on the list of the Seven Square-Enix Character.
I got to realize the effect of the "Smash Bubble" community, for years people have been in influence of "Hardcore Nintendo fans" which lead them to believe that Square-Enix would be either Geno, Chocobo, Black Mage or a Snes FF protag, or that Square-Enix are vilain of some sort and such. Alongsides TONS of misconception about lots and lots of stuff (When we didn't know that Smash Ultimate would be called Smash Ultimate)
Literally everyone and their grandma saw Cloud as a cut, and I remember it clearly, EVEN If you told them that cutting Cloud would be a suicide move with how big the character was, everyone just closed their eyes and put their hands on their ears and didn't listen.
Same happened for Joker, where before ultimate pre-release some of us would amuse the idea he'd get in, only to be slammed and even mocked for thinking he would get in before anything Megaten, or Jack Frost or even any others Sega Characters.
And the same once again happened with the desilusion (because there no other way to call this) when people thought Nakoruru would get in before Terry back when the SNK copyright stuff happened...
Sometime, people go too far to try and bend reality for their characters, or just close their eyes looking at data, spread-sheet, sales or whatnot. When in the end, when you look at most inclusion when it comes to third parties...Actually, ALL third parties.
They're recognizable.
They're famous.
They influenced gaming in a powerful way.
Generate a big fanbase.
Like, when you look at all of the third parties in smash
They all had a big impact on gaming, in such an incredible way, that it's all that matter.
People will then nitpick that sentence from Sakurai saying that it's not just being recognizable, but also fun to play.
"But also" that's the part people forget. Terry might not have been recognizable for lots of people, doesn't mean his games didn't influence his Era and the Arcade world alongside gaming as a whole.
That's why I think people should stop thinking about sales numbers, being buddy buddy with nintendo with bazillion of games on the system or what not and if it's going to be someone big or not.
In the end, I'm pretty sure, how said characters influenced gaming as a whole, in their Era or forever is what matter when it comes to third parties