Average in skill or Average in personality?
In personality then yes, definitely Fedor, the guy just behaved as an average guy and didn't have anything particularly outstanding about his attitude or physique.
Saying Fedor is average on skill though? A man who has won European, Russian and World sambo gold medals several years? Who at his best went through an epic run in pride and to this day is probably the most complete HW who has ever competed in the sport.
If you are talking about skill then most definitely Michael Bisping, the impressive about Bisping is his willingness to keep trying until he finally became champion, something his skill set never really showed he could achieve. His tenacity is his best technique, this guy is the least impressive champion since Dave Menne, he does not have one move that's actually impressive to see. Mighty Mouse has his speed (and everything else) Conor the striking and precision, Cody his boxing combos, Cormier his wrestling and well rounded game for his size, etc. Even in the horrible HW divisions we have know, Stipe has his power, Overeem as well, Werdum his jiujitsu, etc.
Every champ has something impressive but Bisping has shit, all he has is a loud mouth and the self belief that he can become champion and managed to do so. Which I still cant believe.