LOL. Of all the UFC WW's to pick, you went with Anthony Johnson in the Top 5? Nick Diaz is not a Top 10 WW, he's barely fought anyone, and if he went to the UFC he'd be exposed and bumped out of the Top 10 talk for good. Nick would get beaten up by GSP, Fitch, Shields, Koscheck, Penn, Alves, Hughes, Kampmann, Condit, Stun Gun, Story, Hardy and he's already lost to Sanchez. He would not be in the top tier of the UFC's WW division, and he knows it, which is precisely why he signed a new 4 fight deal with Strikeforce.
This plus Lytle, Ellenberger, and a healthy Swick. I wouldn't say it is out of the question that several guys below them like Volkmann and MacDonald could beat him also.