I think its unfair to say that theyre mediocre. Both are excellent and could make a strong push for top 10 in the world (6 billion people + ) so they are by no means an easy task. Werdum is mocked for losing to JDS, who is being touted as anything from 1 - 3 in the world so wheres the shame? Bigfoot is going to be very difficult for anyone to beat and is getting better all the time.
People need to remember that Fedors prime wasnt just a few months ago, it was years. Years that can change a person so before you know it you are actually living on past memories viewed on Youtube. At his best he was unstoppable but, lets be fair, he was exposed against Andrei (who is now a stepping stone at best) and has deteriorated from there.
Had M-1 put him against Overeem / UFC's best fighters imagine what they could have done to him in comparison to the men you label as "mediocre".