Many would agree. I've seen the odd poster label him great. It would make a good thread question. Falls short for me on first thoughts.
Gene Fullmer has never looked particularly good on film, though he has won against some great fighters.
Type in YouTube “Rocky Marciano” chuck a fight on sit back and pay attention to what he does getting to the inside and what he does there. If you try you’ll fathom it pretty quickly.
I’m trying to fathom how anyone can be all those things and still be competitive in boxing let alone win it all. What of the opinions of actual ATG coaches who actually coached and saw Rocky live? Y not take Dundees word of how great he was? Goldman? Damato? They would not agree with Emmanuel’s uneducated non first hand take.