Honestly the fact that Corbett was able to be viewed that way so consistently by pretty much everyone who saw or trained with him despite looking as he does on film makes me rate him even higher. I feel like someone would’ve called him on his bluff at some point while he was still in the boxing scene as an older man. But yeah, still definitely overrated.
For me it's more that he's usually referred to as a great technician over decades when it just seems to me that he was really fast all round. I don't think the old footage does him justice in that regard. I think it's the classic misconception of speed = technician which people still make today.