Carroll, Sherman, Wagner, Chancellor, Earl Thomas, KJ Wright, Bennett, Avril, Lane.....on offense, obviously Russell Wilson, Doug Baldwin, Jermaine Kearse, and now pieces like Garry Gilliam, Thomas Rawls and whomever helps him at Running back, and ironically pieces like Jon Ryan and Hauschka are pieces that are going to be the baseline of the offense/special teams.
This "core" group is in their prime, approaching their prime or capable of playing at a high level for the next 3 to 4 years. In order for this extension to go beyond this 4 year run, it will be up to players like Ifedi, Frank Clark, Jarran Reed, Glowinski, Vannett, Alex Collins, Prosise and others to bridge the gap and get added to the core group above. At least 2 of the above players must be Pro Bowl borderline or caliber pieces to make this run truly successful.....add in an occasional trade by Schneider for a Sammy Watkins type of disgruntled piece that is elsewhere and you add years to Carroll's career.
If you measure the NFL timeline, if Russell Wilson progresses on the field over these next 3-4 years, Carroll will continue to coach beyond this extension.....great coaches don't leave winning QB's in the prime of their career. If Wilson levels off and doesn't take the next step of development to supplement the core of the defense, this is a 4 year "window".
I have a feeling Carroll will be around for at least the next 6 years and a couple of additional Lombardi trophies get added to the Great Northwest. Somehow our friends in Arizona, LA and SF have to be wondering when their window will open to compete....I don't see any of those franchises closing this gap or with windows that are going to truly match up each and every year.
I see Carolina, Seattle, Green Bay and perhaps Arizona (if they can replace Carson Palmer and Fitzgerald in the next year or two) as the contention in the NFC the next 4 years....Can we stay ahead and get back and will Carroll/Bevell outlast Arians, McCarthy and Ron Rivera??