You are right, that is why I put him in top 3. But, I was saying I cannot put him at number 1 because ranking and how one perceives a performance is subjective. And even though the general consensus I cannot rate his performance on my own. I rank him high do to reputation, reports and Resume, but I cannot rank number 1 without film.
As great as Sugar Ray Robinson was, he was just passing through the middleweight divion. I would not include him on those grounds.
During his brief cameo at middleweight Robinson managed to win the championship 5 times, so I think he's probably worthy of consideration.
Greb easily went up and fought Lightheavies (Supermiddles today) and would cut down to defend his MW Title. This content is protected + This content is protected + This content is protected = 116 rounds boxed 971 Greb would have been a big fighter for the other MW champs to handle.
No doubt, he also lost a few at middleweight. Just to mention that Hagler, Monzon and others defended the title so much longer.