Not even that since even the last game included franchises like Punch-Out!!, Duck Hunt, and Mega Man, the former two of which don't have a future and the latter would not either had the fans not spoken out in the Japanese Brawl Poll that got Sonic in. Literally the only advertisement character we got was Corrin.
But the thing about those three franchises is that they were actually significant to Nintendo or even video game history so of course their inclusion makes sense. Golden Sun is your everyday RPG franchise that only got sequels because the GBA didn't have a fuckton of them like the DS and 3DS and being released near launch when there's nothing else to buy. When Dark Dawn actually had to compete with other RPGs, it tanked so Nintendo told Camelot to pull the plug and become a Mario Tennis and Golf factory or they can fuck off.
Yet people think Isaac is entitled to a slot, as if adding him in is going to bring tons of customers groveling their feet for the next Smash. Anyone who genuinely thinks that Smash needs a niche RPG characters, or anyone who's not a newcomer in Smash yet, deserves mockery for thinking Smash revolves around their favorite characters.