Why is everyone dismissing his chances against Silva?
Rashad is one of the very best, better than Sonnen I'd say, at timing takedowns and finishing them. He has a better top game than Sonnen, and is far more comfortable on the feet.
Fight IQ. Most of the time he's smart enough to use his wrestling and take it to the ground, but every once in a while he has an epic brainfart and decides to stand with a better striker. His top control and ability to do damage on the ground is also a bit lacking, he had Phil Davis in the mounted crucifix several times for over a minute each time and failed to put a single mark on his face. When you have someone in the crucifix for that long, he should be either finished or beaten half to death.
Then there's his standup, which for all its speed & power is fairly basic and flawed. I'll link to Jack Slack's breakdown
since he does a better job than me. Anderson Silva should be able to capitalize on those flaws.
As for a MW win guaranteeing greatness? I'd say only if he can hold onto the title for a few years after he wins it. If it's another one & done like his LHW title it doesn't really count for much. Randy Couture had successful defences on both of his titles, BJ held the LW belt for several fights until Edgar took it away from him. Matt Hughes and Chuck owned their divisions when they had the belt and Anderson and GSP rule over their divisions these days. If Rashad wants to be spoken of in the same sentence as those guys, he'll have to do the same.