Silva said before he weighs around 210-215 normally before cutting to MW, but there are a lot of big guys in the MW division who will weigh similar. He bulked upto 230 but a lot of that as people say is probably water weight and fat before cutting to make himself sharper to fight at 205.
He seems to be trying to do a Roy Jones (his idol) and go up and down in weights but we all know Jones was undefeated and should've retired yet he kept bulking and losing it and it affected him a lot, he lost most of his fights in the last few years, its not a good thing. Although the LHW division has a lot more challenges for him and I can see his motivation for it, also tyring to be a 2 weight champion in MMA is very difficult and very rare so he might want to achieve something that not many have (has only Hendo done it?),
IMO Fedor is no.1 p4p, but Silva is probably no.2 when on form, he has improved a lot since his early pride days.
As a striker, he is probably the best in MMA, his BJJ is pretty good, he lacks wrestling but thats because he's a striker, so if your talking about p4p in terms of skillsets then he wouldn't be no.1 but p4p is about results. He has been very impressive. You can't say anyone who has good wrestling and BJJ would 'easily' beat him, thats just silly, first of all he is more like to 'easily outstrike' those oponents you have meantioned than be 'easily beaten'. Although it showed in the Hendo fight he can be taken down and kept down, who could do that for 5 rounds? or even 3. He is likely to hit you if you come in to take him down and thats where his striking is most dangerous, he can also clinch if you get close to him, so once you have done it he won't let you do it again, as shown in the Hendo fight.
In pure wrestling/BJJ many fighters would beat him, but this is MMA and he would beat them all in striking and thats what has had the upper hand in his fights.
You could even use the arguments that he has some weaknesses yet he has beaten his opponents soundly, so instead of using the argument against him it actually works for him.