Canzoneri looks marvelous when he is doing well. But he did seem to have more off nights than Ortiz. And Ortiz was absolutely top notch. I am going to lean with Carlos.
Canzoneri has all the tools to bother Ortiz, with his magnificent positioning, baiting, speed and underrated power, but Ortiz is also at the highest level of 135 fighters. His consistency will definitely let him work in to Canzoneri, ala Ross, and pick up points. Both have ring IQ on the highest level - there would be a lot of posturing and some great set up and action from both. Either man can win this, but I can definitely see Ortiz with a Split Decision. Same with Tony, actually.
I think Ortiz has an edge, but only because he is a true lightweight. Tony at his best was a true junior lightweight. Since their skill levels are so close, I give a very slight edge to Carlos because his strength advantage makes it more likely that he will be able to gradually impose his will over a 15-round distance. I say this even though Tony is among my all-time favorites.