A fight with Cormier would have a good chance of going the exact same way as the Cain fight, Cormier now knows exactly what he has to do recreate that. I would like to see Junior fight once first before fighting either Cormier or Cain again.
I really don't know what I would do with Junior right now... Overeem would be the obvious choice if he loses to Big Foot. Hunt would be another interesting fight. I think a Werdum rematch might be interesting, and if anything Fabricio deserves one.
Everyone else JDS has either already fought or would most likely dominate. The Barnett fight doesn't really intrigue me for some reason, I don't think Josh would get him down and he would be beaten on the feet fairly easily. I agree with the majority who seems to think Barnett/Mir makes the most sense.