Hard to say. At the lower weights, Mayorga had quicker feet, and he wouldn't have had to contend with the "size" advantage of Vargas. Plus, I've always thought Vargas' ability to beat punchers was somewhat questionable, seeing as he's managed to get brutally KO'd by pretty much every one he's fought (though I suppose Ike Quartey could be considered an exception).
you can't ignore that Vargas' trouble with punchers was never an issue until post Trinidad. Just throwing that out there. also, Mayorga hit harder at 147, with 8 oz gloves, but at 154 and above, he never showed the power he had at 147. I think Varga's speed and ferocity win him the fight at least by decision, if not by Nando against the ropes signature stoppage.
But is that because he really had no problem with punchers? Or is because he didn't actually FIGHT any real big punchers until Tito? IMO, it's the latter. Campas was only a puncher at the clubfighter level (as most of his big fights exposed), and although Quartey was a decent socker, he was never really an explosive puncher on the level of Tito, and had never scored a knockout/knockdown above 147.
But how many punchers at 154 are at Trinidad's level to begin with? :dunno: I'm not so sure Mayorga is at Trinidad's level at 154 lbs. In fact, I'd say he's not - at all. I think Mayorga's power is a tad overrated. I do think Campas and Marquez are good barometers, as is Ellis. I think a prime Vargas at his best gets through Mayorga just fine at 154. Peace.