Bisping is talented, but he has always been matched up very favourably against mid tier opponents. He has good technical striking, good TD defense and is pretty decent off of his back. Leben/Akiyama were perfect match ups - brawlers who Bisping could stay on the outside with and pick apart. Dan Miller is a tough fighter who is just that - good BJJ but Bisping's takedown defence was always going to force the fight standing. Mayhem turned up looking and fighting like shit, and Bisping looked a bit under par IMO in that fight as well. His losses have always come against fighters he hasn't been matched up well with - Hamill (worst decision ever), Evans and Chael were all able to grapplefuck him, and Hendo had that fight wherever it went - I called a 1st/2nd round KO or a 3 round GnP fest as soon as that fight was announced. Whilst the Silva fight was close, it showed Bisping's complete lack of power - any technically skilled stand up fighter with aggresison will just be able to take the fight to Bisping.
I do think Bisping is a good (not great) fighter who probably floats around top 7-10 of a relatively weak division. I fully expect him to be given Maia next who he will beat on the feet in a decision, face someone like Aaron Simpson who will not be able to pin him down for a great length of time and will win another decision, then lose to someone like Belfort by KO or Munoz by grapplefuck.