I would have Bisping in my top 5 but I think he does suffer from being a jack of all trades and master of none. He is one of the most well rounded fighters in MMA but lacks any real weapons. His boxing and cardio are fantastic but aren't scary to other fighters as he lacks real KO power. A technical strikers with KO power will always trouble him.
I think you probably explained why I always underestimate Bisping. So let me start off with some +rep and a thank you.
I have him in my top 10 (trust me, higher than I have ever had him as my dislike for him and his fighting style had me rank him lower). I think he is clearly #6 or #7, and that he is only another fight away from a top 5 guy to making it to top 5 on my list.
Still I won't underestimate him again. I am still not a fan but I will say this fight removed the blinders I placed on myself about him.