GSP murdered Serra in the rematch. Silva would have murdered those loses in rematches. The same can't be said for Fedor.
10 years without losing a single round which consisted of no name Japanese fighters? That doesn't say much at all. His biggest wins were Nog and Coleman and that doesn't warrant you the greatest off all time.
Fedor always fought sloppy from the beginning and he was finally exposed when he fought in the U.S and his aura should have never really been there in the first place. How close was he to getting knocked out by Brett Rodgers?
You asked me who the greatest of all time is? As much as I don't like him and root for him to get knocked out, it has to be Jon Jones.