Tradition of fighting games mostly. The way the character line up is now I wouldn’t be surprised if there isn’t a traditional boss character and it ends up like Alpha 2.
I think that’d actually be a cool boss. Kinda like God Rugal in a way. A hybrid fighter utilizing moves from both, though the majority would be Necalli’s moves infused with Psycho Power. I’d like to see something like that. I’d even be fine with a souped-up, Alpha 3 like Bison as the final boss in Story Mode. I always preferred Bison as a boss character.
Actually, it would logically be the majority if Bison’s moves but more powerful than we have ever seen them. Bison’s consciousness should take over Necalli’s body, which would cause Necalli’s consciousness to either be become latent, absorbed, or permanently destroyed.
Either way I’d like to see a modern take on the Shin Bison character.
When you view things from the actual timeline of the series not a lot of time has passed from Cammy freeing herself to SF5. Especially considering that Shadaloo went dark and the dolls were hidden away in a secret research facility in the mountains until Juri kidnapped them.