The four greatest southpaws of all time are undeniably (in no order): Pac Hagler Whitaker Saldivar Who would be the 5th greatest?
That's a tough one. I think Calzaghe, Flowers, Winky, Judah and especially Camacho have an argument. With that said, I think Uysk ends up in the top five if Fury ever fights him. He certainly did enough at CW to be in the conversation.
If we are agreeing with the OPs top four then I think Flowers and Camacho are tight for #5. Also, I'd like to throw the criminally underrated Mark "Too Sharp" Johnson's name into the mix.
I could easily see that as he had a very long reign and never lost. Your going to think Im crazy but Hector Camacho was about the most fluid southpaw ive ever seen especially when he won the lightweight title god he had skills. Michael Nunn when he beat Frank Tate looked amazing and when he took Kalambay out I thought for sure I was watching a HOF-damn you Toney. Reggie Johnson was a very good southpaw who fought at the world class stage in multiple weight classes. Man this is a hard one because it can be argued that the above had talent but they didnt reign long enough.
Wow I forgot all about Johnson and he was very avoided especially when he was young. Great shout out.
Now that I thought about it you would have to give it to JC based on he never lost and he was a champion for a long time. Its hard to argue against him based on how long he was at the top and while you might be able to make a case of others having more talent JC had both talent and was on the top for a very long time.
Elorde for me, with mentions for Ebihara, Usyk, Flowers and Watanabe. Watanabe was probably the most skilled and talented overall along with Payakaroon, who was probably even more gifted tbf. Nunn similar. It highlights the problem though that not that many southpaws have been undisputed greats despite there being enough who had great or near great ability but either underachieved, lacked dedication, played it too safe or had bad luck etc. Nunn, Camacho, Gushiken, Calzaghe, Galaxy, Bettina, Tendler, Payakaroon, Ibarra, Zapata, Too Sharp, Rigo etc.