I don't think it would have changed that much with Fedor; he probably would have creamed Lesnar but would have been humiliated by Velasquez. I think White would have reacted much more kindly to his losses, but fans are pretty unforgiving and just as many people would be calling him a can now (most people consider Lesnar a can).
So I'll take a shot at it. I read somewhere that Silva was considering retiring early in his career because there wasn't enough money in it. So what if Silva retired before going to the UFC?
I think we would have a Franklin/Hendo trilogy. The first fight was damn close, and I think Franklin could have won it if it was 5 rounds. Also, there would be an up and coming challenger in Marquardt who could have beaten either guy. Then you have Okami, Maia and Sonnen making waves.
I think riding the momentum of wins over guys like Okami and Marquardt, Sonnen would have won the title. He had the best performance of his career against Silva, and if it was against anyone else imo he wins. Sonnen would be the PPV king right now, and potentially even a main stream celebrity. The fight with Bisping would have been a title fight, and it would kick off a crazy UK/US feud in MMA, and probably a trilogy where the belt changes hands once or twice.
I think if it wasn't for Silva, the MW division would be as crazy and competitive as it was during the Ortiz/Liddell/Couture days.
Zombie is born!