I was dying to play this guy in the early 90's when I heard of him in the UK.
Problem you have is the only people bigging him up are really fellow players who got raped by him. Its really easy to think someone is unbeatable when you never see them lose in your neck of the woods, doesn't mean they are.
No doubt he was ahead of his time though. And guile and ryu are such pure characters to play, so I'm sure he was really good.
I always remember reading about him talking about Guiles standing Fierce punch into flash kick, and that was back in the early 90's which was off the scale advanced for back then.
In fact, its so difficult, even most gamers of today, even most accomplished SF players would struggle to pull it off (more than 3/10) over 20 years on in the earlier versions of street fighter.
A two hit combo, from a game made over 20 years ago, they would struggle, that's how far ahead of time that game was if you got sucked into the meta game.
it also shows how backwards things have gone in many other ways.
Standing fierce to flash it pretty easy iirc on most versions of SF2 without frameskip (non-turbo), though I do admit it feels weird as fuck in comparison to newer games due to weird hitstop and even less forgiving timing..