The whole "he was the best in his era" argument holds no water. Let's say he was the best at the time. Ok, then that's what we'll say about him: he was the best in his day. It doesn't go any further than that, though. His day was weak as hell. I know all you hipsters like to pretend like MMA hasn't advanced much, but it has.
That old English dude that broke the 4 minute mile was a beast. But if we're talking about the top 10 fastes milers in the world, he doesn't come close. He gets props for being a pioneer, but he doesn't factor into a "greatest milers" list if we're concerned about being fast just like Bas doesn't rank as top 10 if we're concerned about guys fighting and beating the best fighters.
Pretty much this, well reasoned. I think Bas gets a lot of credit for being as charismatic as he is, Pancrase had little of the MMA we know today, rules were pretty weird, and was more like a board game than a pure fighting one.
From my point of view, and I'm no expert, Pancrase was a submission oriented competition, he had this bright idea to twist a little bit the rules and use those allowed slaps to strike full force and catch this submission oriented japanese fighters out of their game.
He was good. But he competed in a weird MMA format, against Japanese fighters, and had no career beyond that. He gets too much credit for how charismatic he is.