I think Kimbo would have a much better chance of fighting someone like Silva, or another striker. Mir gave up huge reach to Silva, and broke his arm. He was the champ for a bit before he got into the motorcycle accident. He didn't lose the title by losing to a man, but broke his leg. The guy is serious good at Jui Jitsu.
Teeing off on a guy at the begining of a match, where he is fresh and moving, is not easy...and the guys at this level have been hit with some pretty serious shots...So Kimbo dropping someone with a knockout to start out would be hard. Who is a good grappler/wrestler that he has fought?
I don't think he would fare well against Lesnar or Mir. Mir said after the fight that he thought he could hit Lesnar coming in on a shot before he got there, but when Lesnar changed levels and shot he was surprised at how quick it was.
He does seem to be a decent guy...and he is trying to fix gaps in his fighting...I just don't know if he can do it.
Tank looked like he trained for the fight by going to pizza hut. He ain't Randy Couture for sure...and Randy has him by a couple of years.