one thing about cole is (and this is what separates him from kerr) that he is extremely disciplined with his approach and training. he simply loves fighting and nothing else. he has never been into partying or using drugs (apart from partaking in more than his fair share of hrt 
)/alcohol (read mussolini ), has a family, great dad, is humble, even monastic. that is why he has had a long career.
problem is, he's fighting guys that are just as disciplined and live equally monastic lifestyles BUT THEY HAVE YOUTH. fedor, for example, is a freak and just when you think you're gaining on him, you're really just falling into his trap. the guy has youth, near perfect technique and makes the iceman look like an oven. i have never seen fedor panic. i hate to use what has now become a cliche (thanks to americans), but fedor is a machine.
having said that, there is always going to be questions raised as you alluded to with the headbutt thing.
it is simply fact that coleman and kerr were able to enjoy a brief interlude where butting was legal and eye gouging was tolerated.
kerr particularly used this beautifully and was ferocious. i've never seen a more explosive and effective shoot wrestler in the octagon as kerr. what fedor might today take 3 rounds to do, kerr was able to do in seconds, simply because he was permitted to do it.
shoot in asap, double leg, single, whatever (didn't matter to kerr), grapple and gnp. only when you gnp, you use the head instead of wailing fists/dropping elbows (which are much less efficient at the start of the fight). he would simply use the incredible strength in his hips and shoulders to hold them fixed in position and then drive the butt of his head repeatedly into the face. he didn't beat his opponents with finesse or go for the quick ko by targeting the chin, he would simply bludgeon them senseless until they were just too fucked up to continue.
brutal, but extremely efficient and this is why, imho, kerr is the closest thing to the most pure form of unarmed combatant ever recorded on film for mass media.
Agree man, Kerr in his prime was nearly invincible. Just didnt have the mental fortitude.
I would love to see how Kerr would have done against Fedor when Kerr was "the smashing machine".
