I think if was Bas Rutten who was like "I remember seeing this fat Russian guy who was fighting a guy from my gym. We thought he would get crushed, little did we know...".
Fedor wasn't THAT small. He wouldnt always have been one of the smaller HWs, but his style was exactly like an MMA Tyson. He could take your best shots, and hit much harder every time. His submission defence was almost unmatched (up until the Werdum fight) and he was so solid in every area possible.
What kills me about his losses were they made him look so weak, but they were so understandable. Stretched out, his "prime" wouldnt have been over so quick. Werdum just caught him. Fedor always seemed to slip out, but this one time he didnt, to one of the best BJJ guys around. Antonio was toe to toe with him, and Fedor was eating Silva's best and giving them right back. It was a good war, until he got taken down (which he didnt always resist amazingly, especially not against a huge guy like Antonio). We seen great grappling from Bigfoot, and Fedor struggle endlessly to get out, never quitting and taking insane punishment. The guys stopped it, but it didnt even really feel like Fedor did anything wrong. He got outgrappled slightly, but Bigfoot is a great BJJ guy and outclasses most on the top position. Lastly, the Hendo fight. He dropped Hendo, Dan slipped out, and finished it with GnP quickly. I personally think that had NOTHING to do with Fedor's prime, and could have happened to him at any stage of his career. Hendo literally just slipped out and landed hard enough shots in such quick succession that Fedor couldnt defend quick enough and the ref jumped in.
Harsh to say he dropped off so much but he's truley one of the greatest of all time, in not THE in a lot of people's opinions.