You're wrong about Randy. He was never a guy who seemed unbeatable or dominant. He was the old underdog that everyone wanted to see if he could still pull it off. 8 times he was not able to. Hardly the picture you try to paint.
I do wonder that if someone goes out and drops Fedor, how many casual fans will immediately ditch him. Shouldn't happen, if he loses it will not tarnish the fact that he has dropped 6 former UFC champions, and beaten a lot of great fighters, most of who were in their prime.