Street Fighter’s design team defaults to “blue eyed and blond” whenever they think about Caucasian Westerners.
That gets pretty silly. It seems more fitting for the SF universe if Bison started as human and has just transitioned, through his experience with Psycho Power, to a force that is no longer permanently tied to a single body.
It fits with what we see with characters like Akuma and Oro. Even if you view their pursuit as one of spiritual ascendance, Bison shows someone forcefully creating a physical spiritual ascendance. It also fits with what we see of the Satsui no Hado and Kage in SFV, which pushes forward the idea that the whole spiritual side of SF has a reality to it (and with Kage it even shows the semblance of a sentient self.) (Necalli also pushes forward this idea, but we all know Capcom has already forgotten entirely about Necalli.)
But taking away Bison’s origin as a human diminishes him in my eyes. He becomes just another generic evil force, where as a human he is a warning of a path that humanity can take.
As for throwing Bison back to some body-swapping entity that has existed for millennia, I think that diminishes him as well simply for being so lazily cliche. Oh, its the big bad. What’s his real origin? It’s Cain, or Abel, or Judas Iscariot, or the Roman soldier that pierced the side of Jesus, or whatever.
Similar goes for making Bison an actual Nazi, a WW2 German soldier, or even some Nazi-wannabe, again it is such an overused and lazy cliche to show how “evil” someone is.