You've taken a lot of criticism over this comment but I had a similar thought when reading about Coach Madden's involvement with the game. It was well known that Al Davis held back the Raiders franchise by infusing his 1970's philosophy into a team that tried to compete in modern times. I don't put John Madden on that same level, but I do think it would be constructive to have input from others who have current/recent coaching and/or playing experience on the pro level.
Anyone who watches the NFL can say "Oh, the bubble screen is trending this year," or "Rugby punts are something we need to add because teams do that now," or "The nickel back should line up here because that's how it's done in a base defense..."
John Madden's experience is either in the past or on a viewership basis where he doesn't understand modern schemes and modern philosophies to the extent that is possible.
He never coached/gameplanned/scouted any of the current players and/or coaches that run the present NFL game. I doubt he has taken the time to break down modern day blitz packages or coverages. As a commentator he may have been the guy who used the telestrator to help "educate" viewers, but he doesn't go to the levels of a Chris Collinsworth to really explain the "why" and the "how" of the intricacies of each play.
John will tell you that Marvin Harrison was supposed to be here and usually is there, but sometimes he's not going to be there.
Chris Collinsworth will tell you why he should be there and why he was or wasnt, and what the other team or players did to make that happen.
Schematics/philsophies are evolving on a yearly basis in football. Coach Madden isn't breaking down film and drawing up adjustments on a weekly basis anymore. He hasn't done that for decades.
The game is in the present and moving forward. Madden has good fundamental insight, but he lacks the present day knowledge and innovation that is alive in younger, more recent coaches and players, etc.
I respect John Madden and think he does a fine job providing input. But we need some modern day John Madden's riding shotgun to help bring the X's and O's of the gameplay along.
The fundamentals and basics of the game may never change and for that reason Coach Madden is a great asset. But his contribution can't reach a dynamic level like that of someone with more recent experience and input.