While for the most part I would agree with you, I think at some point Kimbo would bum rush Tim and ground and pound his ass after a brutal takedown, he's (from what I've seen) pretty driven and ferocious, would love to see that match up.
he could definitely bum rush tim and he has the chin to eat a few coming in, but then what?
tim is no expert on the ground but he's got enough tools to nullify anything kimbo brings to the ground, if not submit kimbo or even gnp him. don't underestimate tim's ground skills or overestimate kimbo's.
i've only seen kimbo on the ground once (i'm not even going near the gannon fight) and he was atrocious. if mercer knew how or had the strength (compared to kimbo he was completely outmuscled) to hold a cruicifix he would have owned kimbo.
tim has the size, strength, skills and experience to incur no problem at all with kimbo on the ground. at the very least he stalemates and the ref stands them up again, kimbo goes back to eating tim's broom stick.