#1: Pete Carroll
Without Pete, this team doesn't exist. Without Pete, John Schneider might still be in Green Bay. Without Pete, we almost certainly wouldn't have the caliber of assistant coaches we have. Think about the value Tom Cable alone has brought us. Without Pete, you aren't finding mid to late round diamonds and polishing them into megastars every year. No Pete, No Richard Sherman. No Pete, and possibly no Russell Wilson. I could also see many other NFL coaches overruling their GM's regarding a 5'10" QB, and very few would start a 5'10" QB as a rookie. Few coaches know how to put players in position to succeed like Carroll does. He's also built what has to be the NFL's very best locker room environment. Carroll is a visionary who in just 3 years not only transformed one of the league's bleakest franchises into it's very best. In just 3 years, he went from a has-been college coach to the most influential man in the NFL. He's the new Bill Walsh.
#2: John Schneider
The perfect enabler for Pete Carroll. I think Carroll makes Schneider look like more of a genius than he really is (pretty much all of our late round coups were coach up jobs). That said, Schneider is, at minimum, the hardest working GM in the NFL. I think he has a great eye for talent as well, and I love his disciplined "moneyball" type approach to things. It's really unfair that we have the NFL's best talent developer and the NFL's best GM.
#3: Russell Wilson
I believe Wilson is already the NFL's most valuable player. It's daring to say that now, but a year or two from now it won't be. That said, I think we could probably win a championship with a far lesser QB and if for example we had taken the Matt Barkley route this offseason instead, our franchise would still have a very bright outlook. Wilson is extremely valuable, and I think anywhere else he'd be #1. But he's #3 here.
#4: Paul Allen
Most of Paul Allen's value comes from three things. One, he saved us from Ken Behring back in the 90s. Two, he cares about this football team but is wise enough to leave the decisions up to professionals. Three, he has I think the perfect sense of accountability, knowing to be patient but also knowing when to cut bait and move on with failed hires. There is a 4th role form of value he brings, but we have yet to see it. That final form of value deals with how the post-Paul Allen transition will be handled. If he dies, who gets the team? If he sells before then, who does he sell it to? Hopefully someone that reminds us of Chris Hansen, and not someone who reminds us of Clay Bennett. Obviously, if he screws up on this final point, it makes him easily the most important person in the organization, but not in a good way. Given everything he's done so far, I really doubt he'd screw that part up. So Allen's a massively distant 4th- even John Schneider didn't list his owner when talking about the 3 most important people in the building.