most important things is how much Canelo learned in his fight with Floyd. I'd compare it with what Angelo Dundee said about Ali -- that he Ali that left the ring after taking the title from Liston was a very different fighter than the one who entered the ring. Now, of course, Canelo lost, distinct from Ali's winning. But the Canelo who left that ring is the one that was transformed from a very good, potentially great fighter, to an elite, all-time great. Without that experience, his areer would have been different, including his prime.
It's hard to speculate ..... he entered the ring against Floyd at 180 lbs. Floyd entered at his natural weight, which was around the cusp of welterweight/ junior middleweight at that time in his career. One judge did have it a draw, and literally when it was announced, Canelo said , "It wasn't a draw." He knew he had lost. And the judge, who really had no qualifications beyond being married to a qualified referee/judge, was quietly suspended from judging fights, then went through the process of judging 4 rounders and working her way up. I will give her credit for being a bit more stupid than purposefully corrupt, though it's a close call there -- darned near a draw!
This is just my opinion, but I think of Floyd, at his best, rates at the very highest level, among very few champions in history. Those few guys always find a way to win in their most important fights, when they were fully prepared. I place Canelo in with the elite, all-time great champions, but not at the exclusive top of it. I think that Andre Ward would have beat him. For that matter, I think Dick Tiger would have. They rank in the elite level, too, but not that very thin layer at the top.