I will go a step further really I don't think Lesnar's TD's are that good technically but he is so much bigger and stronger that it doesn't matter, Randy was technically miles ahead of him but Lesnar just used raw strength to push through and I have zero reason to believe he wouldnt have done the same to Mirko, why not cause Fedor had trouble? Of course Miko is bigger than Fedor he is still quite a fair bit smaller then Lesnar though.
Mirko was not that much larger than Fedor, although I see where you are coming from.
The thing is, Randy is much smaller than Lesnar, and much older, too. Brock has a lot of physical strength, no quesetion, it's why he was even able to do anything at all to Randy. The thing is, if Randy was younger, if he was a bit bigger, he would have thrown Lesnar around easily.
Cro Cop in his prime is a little bigger than Randy, and his TDD was very, very solid. He was also young, fast, and explosive. Fedor struggled a lot to get him down, and did you see how easily Fedor threw Rogers around, who happens to be a very large man himself?
Keep in mind, I am in no way comparing Rogers to Lesnar, Lesnar is a better wrestler and he is a bit bigger than Rogers, but Fedor struggled a lot to get Mirko down, yet he can throw solid, top 10 heavyweights much larger than him around like little kids.
Lesnar would have problems getting Mirko down in his prime. Could he take him down? Yeah, it's definitely possible. He's huge, has good wrestling, and a solid build. However, is it more likely that a prime Mirko, who has very, very solid TDD and the best striking at HW and in MMA in general (at the time) would beat Brock? Yes, I would say so.