If you must include GSP, Jon Jones and Anderson Silva in the GOAT discussion with Fedor, you will have to address the fact that ALL THREE OF THEM cut weight to duck better and stronger competition. Fedor ducked no one. There will be those who say he "ducked the UFC" but if you look at the fact that, not including the last two years, the UFC had not paid out any fighter more than a million dollars, why would Fedor EVER fight in the UFC if he was making millions per fight in other organizations. If Dana truly wanted to see how great Fedor was or wasn't, he could have put up any of his Heavyweight Champions in a fight like he did with Chuck Lidell. My opinion is that, because Lidell got smashed in Pride and came back to the UFC and became champion, most fight enthusiasts know that Dana would never want to put a black eye on his organization again. So you just wait it out, Fedor, as all champions, would eventually lose and then you can claim you offered all kinds of money and he wouldn't accept and that all he ever fought were cans. Dana, to UFC fans, is like Jon Jones and the bible: they just pick and choose which lines they want to believe.
You want to be considered the greatest of all time? Duck no one.