I know Pac was a multi-weight world champ by the time he met Roach. Roach was training actors like Mickey Rourke and Gary Stretch. Not sure when Roach hooked up with Vazquez, but Vazquez left him after the first Marquez fight and did much better in the rematches under Rudy Perez.
Pacquiao was an unknown who looked to smash everybody with a big left hand when he hired Roach. Fighters make the trainers anyway. Enzo Calzaghe trained Joe from scratch, and he's nobody's idea of a great coach. I think a lot of elite level fighters know more about boxing techniques and tactics than their trainer does.
This doesn't answer my question. Plenty of trainers from Manny Steward to Ignacio Beristain have long track records of raising fighters from kids to amateurs to P4P champions. Detroit hadn't seen a champ since Joe Louis until Steward and it went on to see a dozen from that area while he was there. His nephew is elevating prospects as we speak. Enzo literally raised a fighter from a kid to a champ. No examples for Freddie.
Enzo took other fighters to decent levels whilst running a small gym in a small town near Cardiff. He did great with what he had.
Roach has none to my knowledge. I’m not saying he’s a bad trainer but he’s not an all-time great because he didn’t raise one from youth to the big time.
Roach cut his teeth under Eddie Futch and Thell Torrence. Most of the guys that came to that group were already pretty seasoned guys. Futch and his team were not wasting time on anything less than elite talent. If you are looking for current trainers that truly took guys from scratch look at Dan Birmingham. He worked with both Winky Wright and Jeff Lacy when they were young fighters. Kevin Cunningham out of St Louis also did the same with Cory Spinks and Devon Alexander. He was with both from the Am's to the pro's.
You can't really judge his greatness by that. Once he broke off from assisting Eddie Futch, he was in pretty high demand to work with already established fighters. Why would he try to develop some kid when he could work with high level talent for considerably more money.