Am I the only one who thinks that Mezger at his best could give Machida a LOT of trouble? (Assuming his chin holds up...)
Because while Smith was a powerful slugger that Machida could counter to death, Mezger was quick and slippery when he wanted to be while still maintaining pressure. Watch how he harassed and dropped Liddell--a counterpuncher who fought well on the retreat--before his own chin gave out. At times, he forced Liddell to come to him. Mezger threw both his punches and his kicks in combinations, from odd positions, and with a good balance between high/low and kicks/punches. This is especially true of his hooks--punches that Machida's training and tactics seem to leave him more vulnerable to (he moves straight back, and Shotokan doesn't deal with looping punches well, nor does it score them in competition). Machida's knees usually come in single shots, so I don't see him grabbing Mezger when he ducks under a punch and Thai clinching him to oblivion like Silva tried to do. While Mezger never possessed top-notch wrestling, his takedown defense seems adequate enough to stop Machida from getting the takedown in a clinch. He also has experience dealing with the faster, flicky kicks that Machida throws (and his ability to throw his own fast, flicky kicks makes it less likely that Machida can counter them as effectively as the Thai kicks he usually deals with). Since Machida rarely (ever?!) presses a fight, this might devolve into a tactical match. While I'd still favor Machida by a wide margin, this tempo makes Mezger's chin less of a liability than it would be against somebody like Wanderlei Silva, and allows him to make the most of his own assets. (Maurice Smith, on the other hand...)
Mezger had all of the tools early on to compete with everyone. His problem was that he didn't have real knock out power - and he was learning leg locks with Ken Shamrock instead of going straight into jiujitsu. He definitely would have matched well with Machida because he would have been able to read Lyoto's feints and combinations better than most. I still think Machida would have caught him sooner or later and put him on the mat - much the same way Wanderlai Silva and Chuck Liddell did!