You want us to look at his fights in the context of the MMA landscape at the time as evidence of how he will be victorious in today's MMA landscape?
Yes, he was ahead of the curve at the time, but that was a different time. Fedor fought some great wrestlers at the time, but that was pretty much the only thing they were good at. Mark Coleman and Kevin Randleman were strong wrestlers with knockout power, but could easily be submitted by Fedor, since he was a better grappler. If he fought a good HW wrestler today, like Cain, he would meet a guy who has a complete MMA game adapted to fight in a cage, with insane stamina.
The grapplers he fought at the time, like Nogueira and Arona could not threaten with much else. Frank Mir and Fabricio Werdum have much more to contribute with. Werdum already beat him by submission in 69 seconds, but also has the ability to punish him on the feet, and the conditioning to go hard for many rounds.
He fought some of the best crossover kickboxers in MMA at the time; Semmy Schilt, Cro Cop and Mark Hunt. Again, they did not have a complete MMA game, and the glaring holes in their games were easy for Fedor to find. Semmy and Mark had 0 ground game, and Cro Cop, although having good takedown defence at the time, was content with stalling in guard as the fight hit the ground. If you look at a good striker in today's MMA scene, like Junior Dos Santos, he has good wrestling/TDD and a (questionable) BJJ black belt. Mark Hunt himself has improved a lot since they first fought.
The sport has changed. Fedor has only four fights in a cage, where elbows were allowed. He has limited training in BJJ, prefering to use sambo and judo as his grappling base. Unlike other old fighters like Fabricio Werdum, Fedor has been reluctant to adapt his training methods. If he made a permanent move to Kings MMA, AKA, Jackson&Wink or something, he could do wonders. We all know he will never do this, and that will be his demise. Can he still win a few fights in the UFC today? Yes, I believe so. He can still be a great fighter, but he is not perfect. He will be undersized at HW, and will face guys with a more complete game who can take him out of his comfort zone.