Honestly the one thing I consistently see from folks is that “Capcom already has three characters, and that’s not fair.” To that I say, “So what?”
Capcom, as a company, has been instrumental to a handful of genres in gaming. Mega Man and Street Fighter are among the most iconic, sure.
However, series like Devil May Cry and Resident Evil especially are not only groundbreaking, but trendsetters for their respective genres. Resident Evil is the most highly profitable Japanese gaming series not yet in Smash, and provides characters, settings, and music unlike anything added to Smash yet.
Then you’ve got smaller series, such as Ace Attorney which is nothing to sneeze at. I’m not sure in terms of moveset potential, but the series has fans, undoubtedly.
I’ve also not been one to look at company, but by series. If the series has played a huge role in the industry, provides iconic characters, provides unique gameplay, unique settings/hazards, and brings in an entirely new fanbase? Do it bruh.
If you prefer one company that’s one thing. But preference has nothing on the actual possibilities.