Actually, Diego wins due to having the better grappling, better stand up, better chin, better conditioning, and better pace. This is a good match up for him, although it's kind of difficult due to it being his first fight in a new weight class.
I think Diego striking has looked much improved esp. in the Lugi Fioravanti fight and I think he may have an edge there. On the ground I have to wonder if Diego is going to be out muscled by Stevenson who is a larger LW. Either way I cannot to see the fight, its free right?
Think about it this way. Florian is smaller than both of them and he finished Stevenson on the ground in the first round. I know that styles make fights, but Sanchez is a better grappler than Florian in my opinion.
Sanchez looked extremely crisp in the Fioravanti fight and I think he will have a striking and grappling advantage in this fight. However, Joe Daddy pulls those stinkin guillotine's off left and right so he has to watch out for that.