As part of my series about burying Anderson Silva, I think it is important to realize that Silva didn't fight many of the best middleweights in the world, because arrogance kept them up at light heavyweight.
Fighters who SHOULD have been fighting at middleweight but can't resist the allure of being one of the big guys include: Shogun Rua, Lyoto Machida and Rashad Evans. All of these guys are about normal sized for middleweights. Much of Silva's best competition never fought him because of, well, ego and an unwillingness to cut weight.
It's hard to emphasize enough how bad Anderson Silva's competition has been. Even guys like Sonnen, who had the skillset to beat him, suffered this bizarre contempt for BJJ and a kind of mental weakness - watch the second fight, after Sonnen misses with the spinning backfist, he falls down and sits there. Like you can take a break in a championship fight! And even guys like Dan Henderson - I mean, I love you, Hendo, but I'm going to be frank, here - well, he's 6-4 in the UFC . . . and if you discount his UFC 17 wins, back in 1998, he's 4-4; that's not the profile of a great UFC fighter, Dan's best years were in Pride). And so many of Silva's fights have been against downright bad fighters, because so many of the best middleweights weren't fighting middleweight. Not just Shogun, Machida and Evans, but guys like Michael Bisping and Tim Boetsch were wasting their time at light heavyweight for far too long. But when Yushin Okami or Thales Leites seems a convincing championship title fight choice, let's face it, your division sucks.
(Even Vitor Belfort, who has been looking like a beast in his last two fights, well, we should remember his pretty . . . mediocre UFC record. If you look at his fights after his first run in the UFC (when the sport was almost nothing like what it is, now), he's 7-5 and has never had more than a two fight winning streak in the UFC. Sure, he's a good fighter, but thinking of him as a great fighter requires a lot of slight of hand.)
Compare to, say, GSP's opponents. Jon Fitch was 15-4-1 in the UFC. Josh Koscheck is 15-7. Matt Hughes is 16-6. GSP's next opponent, Johny Hendricks, is 10-1 in the UFC. But even when you compare the best fighters in Silva's fightography you find that . . . their records are pretty mediocre.
Compare THAT to the UFC records of Lyoto Machida (11-3 in the UFC) and Rashad Evans (13-3-1) - bearing in mind both fighters are fighting above their weight class!
Silva is a very good fighter. But when you look at the relative level of his competition, it really stinks and, specifically, key fighters who should have been fighting at middleweight were fighting at light heavyweight. This tendency for fighters who should fight at middleweight to fight at light heavyweight has made LHW a very interesting division, but drained MW of most of it's best talent. In many ways, MW is where fighters who can't win at LHW go, since so many LHWs are small for the weight class.