Here's a theory I've been thinking about for a little.
Biggest Options Theory
Biggest Options Theory is simple: That each third-party character is
one of (Though not necessarily
the) biggest options their company has to offer. There's two definitions of "biggest option" here: Impact and recognizability in the overall industry, and popularity in the Smash fanbase.
Let's look at the third-parties so far:
- - From arguably the most well-known stealth game and highly influential for storytelling (Though he could've been an exception due to being a Kojima request, he still fits regardless)
- - Was Mario's rival back in the day, immensely popular request, Sega's mascot
- - NES legend, one of the biggest requests back in the Smash 4 days, one of Capcom's mascots (Or at least he was)
- - Easily one of the most recognizable video game characters period, Bamco's mascot
- - Mr. Fighting Game himself, one of Capcom's mascots
- - Mr. JRPG, cited as being having the most requests for a Final Fantasy character
- - A potential exception; She was supposedly chosen for the ballot, which would give her the edge in popularity, but there's also the possibility that Nintendo chose her in advance to push her series, which Nintendo helped fund.
- - NES star, did well on the ballot
- - Sort of an exception; He was an easy clone who Simon took some moves from. Though, he's basically just a Simon alt so we can count him out.
- - The original Echo Fighter; Though, as a borderline-semiclone, he's still fairly easy to make compared to most of the fighters listed here, so we could count him out too
- - A recent success, he's been heavily pushed by Sega lately. If we narrow it down to Atlus specifically, his home series is easily their biggest IP (Sorry SMT)
- - Representative for the defining JRPG, a cultural phenomenon in Japan
- - Extremely popular, constantly topping polls since the Melee era. If we go for Rare specifically, I think they're easily their most recognizable creation
- - The mascot of SNK as a whole, despite his lack of relevance in recent games.
- - The biggest game ever
- - One of the most iconic villains in gaming, and has one of the most iconic boss themes to boot
Based on the 14-16 characters so far, we can predict that future third-party characters will also be the from the biggest games in a company's selection and/or the most frequently-requested characters they own.