A JDS fight is stylistically a worst fight for Mir than a Cain fight.
For Cain fight, chances are higher than for Mir to pull off a submission IF Cain decided to toy with his guard and attempt to control him on the ground.
For JDS, he will definitely keep the fight standing and try to Knock Mir out. And with his TDD, I doubt Mir is able to take the fight to the ground for him to use his submission skill. Of course, not forgetting JDS has a "implied" good BJJ as well.
But yes. I agree that Mir is possibly the next most deserving guy in the UFC HW division right now to get a title shot base on record wise. Perhaps, JDS also wanted Mir just to avenge for what Mir did to Big Nog (although it really isn't Mir fault for Nog not tapping)