A definite ATG, super human endurance, excellent skills, great chin, wasn't devastatingly quick or powerful, but he could counter with the best fighters in history, he had a outer worldly ability to anticipate where his opponents punches would go and either beat them to the punch, or slip and make them pay dearly with his precise counters. A top 5 ATG at the Featherweight limit. But he may not have been the best Featherweight in the world when he was alive. I believe Esubio Pedroza would certainly have given him hell, if he didn't beat him outright. Pedroza is the Featherweight from that time period that doesn't get the credit he deserves. Not Sanchez.
Dmt's video says it all. Sanchez is one of the best fighters I've ever seen. He also had an absolute granite jaw. Only complaint is that he was so relaxed and composed in the ring, he seemed to fight down to worse opponents. He was a marvel.
He isn't overrated. He had just crossed over into the sports conscious.. right behind Leonard, Hearns and Hagler. Fresh off a win over the GREAT Azumah Nelson. Stamina off the chart.
He was great, though the sad part is his untimely demise might have obcured the problems he may have had had he moved up. Can't see him beating Camacho, Verderosa, Davis jr, or Mayweather, though Limon, Chacon, and Serrano is doable. And he may have lost to Pedroza, which will always be hotly debated.
He had the potential to be top ten pfp ATG had he lived. He was extraordinary. Few fighters ever have such a calm demeanor in the eye of a storm. A bit like a Mozart/prodigy.
I think Johnny's speed, and unorthodoxity would cause Salvador problems. Plus, I feel that he hit harder than Salvador. Most likely, this fight would be a 12, or 10 rounder, and I think in that amount of time, Johnny would do enough for a unanimous win.