Belcher, boetch and franklin are not good?
Bisping is good too. He arguably beat sonnen, a guy who is fighting for the LHW title.
Silva beat dan henderson and chael sonnen out of the weight class. Yushin Okami is THE gatekeeper. Decent stand up and stiffling ground control.
Now you tell me what a stacked division and list some fighters, and i'll reply with a similar reply as yours.
Dont forget rockhold and jacare.
Belcher, Franklin, Boetsch, and Bisping are good fighters, but they aren't great fighters. None of them are elite in anything. Much of what makes a division deep is the amount of great, well-rounded fighters. These guys don't fit that mold.
Silva didn't beat Hendo out of the division. He went on to beat Bisping and Palharres, then went over to Strikeforce over a contract dispute and lost to Shields. After that he realized he had more energy at 205 and moved up permanently. Sonnen is a very flawed fighter who shouldn't have even done as well as he did at mw. With his awful striking and sub defense, he would have never gotten near a title-shot if he were in any other division (the lhw title shot he has now doesn't count, he didn't deserve it).
Lightweight is a stacked division:
Benson, Edgar, Maynard, Diaz, Guida, Cowboy, Pettis, Guillard, Miller, Lauzon, etc are all dangerous fighters who have elite abilities in one or more aspect of mma.
Welterweight is a stacked division:
GSP, Fitch, Hendricks, Ellenberger, Condit, Alves, Kos, Diaz, Kampmann, Maia, McDonald, etc are all well-rounded top fighters who have elite abilities in one or more aspects of mma.
Lightheavyweight is a stacked division:
Jones, Machida, Rashad, Shogun, Davis, Gus, Rampage, Glover, Bader, etc are all dangerous fighters who have elite abilities in one or more aspect of mma.
Guys like Belcher, Franklin, Boetsch, Bisping, Okami, Rockhold, and Munoz are not elite in anything. They are all slow and predictable. They come from the Forrest Griffin school of fighting -- that is, being decent in several aspects of mma but not excelling in anything enough to put the opponent in any real danger.
Outside of Anderson, Belfort, Lombard, and maybe Weidman, there are not that many notable fighters at mw. Face it, the division is just weak... always has been. It gets more washouts from the heavier division (in this case lhw) than any other weight class.