There's a few I'd like to see as a Diaz-disliker:
Maia - to show Diaz what real BJJ is.
Rory - to just absolutely smash Diaz and send him packing.
Hendricks - to KO him when he tries to hands-down taunt him. I'm not buying into Hendricks "I can KO anyone" hype but he'd definitely drop Diaz and could wrestle him either way.
FITCH - if he complains about being wrestled and outpointed, getting blanketed by Fitch would be the ultimate torture for him. I'd want Fitch to just take him down, make his way to the cage, then slowly move for position, for fifteen minutes. Diaz retires after a tantrum after the fight.
To make it fair I think Diaz would beat Kampmann convincingly.
Nick vs Rory would seriously be EPIC!