When he is healthy and comes to play, Karlos Dansby is the premier defensive player on the Cardinals without question. He is a three-down linebacker who makes plays all over the field and has really come into his own in Clancy's 3-4 schemes. He can blitz, cover in the pass defense and is the best or second-best open field tackler on the team. It will be criminal if Rod Graves and Michael Bidwill can't get a deal done with him IMO.
Adrian Wilson is an intregral part of Clancy's schemes and he knows how to use him. Offenses have to account for him, and he is a pro-bowl caliber player and a fierce competitor. Probably the second best defender.
Then you get to Chike Okeafor, Darnell Dockett, and Gerald Hayes, who all are vitally important to the defense. Hayes is probably the hardest hitter on the team. He's a solid run defender and good tackler. Dockett gives great effort, and should be even better when used in a rotation and with Okeafor lining up beside him.
I've seen nothing from Gabe Watson to think he needs double-teaming by opponents, and that is the mark of a good to great nose tackle IMO. On the contrary, teams were double teaming Dockett a lot last season.