Russell Wilson: Is the Seahawks Quarterback Worth the Money?

Russell Wilson and the Seattle Seahawks went to two Superbowls early in his career...but haven't experienced the same success once he began to sign contract extensions. There's a very real notion in the NFL that when teams pay their franchise quarterbacks more than 13% of their salary cap...the team begins to decline. 

This season...Russell Wilson will account for 16% of the Seahawks cap. Is his contract the cause for the slight decline in Seattle? Or...is he the exception to the 13% rule when it comes to quarterbacks?