I disagree. That's due to two reasons, and Manassa as you have always been courteous to me I will explain for you and hopefully avoid being flamed
I pretty much go from Joe Louis onwards. I'd say around the 30's to now. This being because this is when I feel 'modern technique' really started. I understand this is a totally subjective reason but I hope you understand my reasoning.
The 2nd being because I rank not only on resume but skillset/ability. For me, Robinson not only has an impressive resume but also looks absolutely fantastic.
Ezzard Charles runs him close, but I have Duran at no.2 and Armstrong at no.3. I have Charles 4th and Jofre 5th. My list always changes mind, and I don't think anyone will ever be able to make a conclusive list as........well there's always a new piece of information that comes up and so many fighters have very good resumes. When you get to 20 onwards it's pretty hard to decide although I have a pretty tight top 30. Sure it will change if I look at it again so best to look at it in a year and laugh and whatever naievities (SPELLING???) I had or glaring omissions I made