Rematches are almost always awesome, and if things go the way that I hope, Frank Mir will be laying in a smashed up heap on the floor when the final bell sounds.
Let's get this out of the way right up front: Mir beat Lesnar the first time around, and I will give him all the credit in the world for making the genetic freak tap. Furthermore, he followed that up by being the first guy to put Antonio Rodrigo Nogueira on his ass to earn half of the UFC Heavyweight title.
Now that that is over with, Lesnar is a human monster who possesses the strength to shatter orbital bones with one punch (see Herring, Heath) and the ability to take punches from one of the best ever (see Couture, Randy) without really flinching.
The battle here is clearly going to be Mir's ability to utilize his jiu-jitsu against a bigger, stronger, faster opponent in Lesnar. Yes, he's done it before, but some would say Steve Mazzagatti and Lesnar's inexperience had something to do with it.
Standing and trading with Lesnar isn't really an option, in my opinion, just because he's massive, has shown he can take a punch, and the whole shattered Heath Herring's orbital bone thing I mentioned before. Did I mention he's massive?
To me, Lesnar is the next evolution in Mixed Martial Arts, a heavyweight equivalent to Georges St-Pierre in terms of freakish athleticism. Remember when GSP was just the better athlete than everyone and got by on that and improving talents? That is Lesnar right now. Mark my words.