Ok, I'll go out of the way to defend Whitner, He lined up at basically every position in the secondary at some point, due to injuries and general ineffectiveness of certain players over the past few years. His stats may look like they are going down, but that is in large part because QB's don't throw his way all that often, they picked on McGee, Ko, and the linebackers underneath more. He is asked to different things than most traditional strong safeties, so his stats reflect it.
At this point, he is not a game changer, but he can become that if he actually learns one position in a scheme that stays consistent. however, i think he is better than a few of the safeties listed above namely Weddle and Phillips.