Between two of the biggest punchers @ 135 how do you think this fight would have played out? You have one guy who had a good career but fell short to fulfilling his full potential due to drugs, and the other guy whose career was cut short but has gained mythical status. I think Rosario proved that his power was more potent against better opposition. Valero was heavy handed but relied on an accumulation of punches from weird angles, although he was more aggressive. Would have been a hell of a fight. I'd give the edge to Rosario.
Rosario would have absolutely destroyed Valero. Valero wasn't particularly hard to hit, we saw that several times from Japanese level scrubs to Antonio Demarco in his final fight. What would even make someone think these two fighters were in the same tier, or ball park? Because Valero has that record that looks fantastic on paper?
I think you almost need to dismiss Valero's record - folk will either say he's an unstoppable KO machine because of his record or he's a joke who fought no one. The truth is that whilst his power appeared real, he was a pretty average boxer in terms of all around skillset from watching his fights. There was certainly nothing to suggest he warranted conversation with ATG's. He was a fairly limited banger.
So? Broner also stopped Demarco, with less of a struggle than Valero. The likes of Barthelemy also far more easily outfought/outboxed Antonio than Valero had done.