Napoles past '71 could easily be thought of as too methodical and rhythmic and open to exposure by such a fighter as Aaron Pryor. I'd propose that Napoles was less and less explosive into the mid '70s and it was his overall class and experience which saw him through. Ten years previous to the end of his reign he was vigorous and speedy, but unfortunately the footage is limited. I can seriously imagine Napoles countering Pryor with combinations and winning most mid-range exchanges while commanding centre stage.
Napoles would have given the hawk a boxing lesson, taking advantage of his wide open buzzaw style. He'd take pryor apart piece by piece until there was nothing left and illegal substances couldn't help him . Pryor may have outboxed arguello but that wouldn't be very likely at all against napoles, and even if napoles couldn't knock him out he would have won a wide decision.