He did nearly always bleed when fighting, and that is partly why he was 39-9; seven were cut related stoppage defeats.
That is like saying what if Rosenbloom could punch?! what if Patterson had a chin?! Yes, things would be different, probably a lot. I think it is hard enough to pick a winner in fantasy fights that could have happened, without changing the make up of a/the fighter(s). Minter cut up a lot, even when winning. Everything we know about Benetiz suggests that if they had fought, that would be a factor. Also you further handicap Minter by suggesting it is 1980 Boom Boom showing up, and albeit with over forty years of hindsight, Alan probably was past his best by then too boot. And yes, Benitez was not quite the fighter he was at 140, but the 154 Benitez was still a very fine fighter in 1981. As a fellow Brit, very much at the top of his game, found out that year. But then, perhaps that should not be a factor, as I never saw Benitez finish off top class opposition with one punch!
Benitez has a chance only if he moved up to 160 a few years earlier than he actually did. It's hard to say how good Benitez could have been at 160 because by the time he got there, he was pretty much shot and in serious physical decline.