See I think him being a natural 205 is a big reason why he will dominate. If you walk around at your fighting weight, you dont have to cut or bulk or put any added stress on your body. The bigger guys have it much tougher imo. If they have to fight at the same weight, what difference does it make how much they walk around at when not training? Pointing to boxing, its a big reason why Bernard Hopkins is still a pretty good fighter at age 45.
Also with regard to Silva not being tested- I agree, the 185lb weight class is pathetic. However, as I noted above, Henderson owned Wanderlei and Wanderlei destroyed Rampage twice who destroyed Chuck Lidell. Henderson didnt get out of the second round against Silva, and Silva was the first guy in history to submit Henderson. I think Anderson will have a tougher time at 205 because its the deepest weight class in the UFC, however, I dont think it matters- I still believe he would beat most of those guys pretty soundly.