Canelo had a run at 154 before beginning to cheat the scales with catch weights and bull shit. How would a fight against a prime Vargas look like?
While Canelo is obviously a greater fighter, head to head and @ 154 I think Vargas wins a decision. Canelo's defense hadn't got to the level compared to more recent years. Nando's aggression combined with Alvarez spurt fighting would win Vargas more rounds.