That wont go down well but i do think things have gone stale.
In sports in general i believe that that you either need

a) A constant turnover of role players
b) Regular changes of coaches

Players stop listening after a while to the same voice.
Look how many of the teams 'main' players have been on the team a number of years or even rejoined the team from elsewhere.Every team has watched Payton/Brees for nearly 10 years now and often know whats coming. Things need shaken up both sides of the ball.This is especially true in the modern NFL when most teams can put up 25pts on a fairly regular basis.