Model I would use, if I were the owner of the Cowboys.
#1 -- Find the best talent evaluator out there who is the biggest a$$hole and wants discipline, accountability, and results. Make him GM. Have him get me the absolute best scouts out there. He is also in charge of the coaches.
#2 -- Find the best HC -- who can motivate, discipline, teach and monitor.
#3 -- Find the best "football chess" evaluators and coordinators. Make them the Coordinators. They need to know talent, concepts, and the what to do and why against any and all other talents and concepts.
#4 -- Find the best football teachers. Make them position coaches. They need to be smart, and efficient.
#5 -- Find the best capologist and lawyer to negotiate contracts.
#6 -- Get the best strength and conditioning team. Games are won in the offseason with work.
All contracts both coaching and players would have winning tied to them.
Coaches do not have a salary cap. Why have the most valuable franchise in the world and skimp anything on coaching? Pay coaches for the job they do, eliminate the want to be a head coach because of the money. Head coach, coordinators, and position coaches have three totally different roles and skill sets -- failure mainly happens when they want more money/power and go to a position they are not qualified for (see Wade Phillips who was an awesome DC but eh HC).
Use free agency to better one or two positions each year based upon need.
Design the offense based upon the talent you have. Be versatile. Keep accumulating the talent and use it. Be able to run so you can control the clock and help your defense get rest. Be able to use screens to get outside the box. Be able to get in the seams. Use simple concept reads and flood zones. Throw the deep ball at least a couple times a game to keep teams honest and not playing under all the time. Need to be versatile and run/short zone/deep, and have the personnel to execute.
Design your defense to be able to show 3-4 and 4-3 and definitely the nickel. Try to keep at least 2 playmakers on the field in hybrid positions where they can play either/or to keep the offense guessing. LB/DE and LB/SS are the way I would go. Lets say we have the current D, but draft JWalker. JWalker/Parsons would be fine with one at DE and the other at LB, or maybe both at OLB in a 3-4, or maybe one giving the other a break, or maybe one at Mike and one at Sam. If you also integrated Overshown/DWilson into that as LB/SS hybrids that had run responsibility first, then short zone or back/TE, then you have an ability to be very good. I want players that would allow you to excel at all the variants of D.
Evaluate your own team first. Build your draft board based upon bpa (skills, heart, injury, intelligence) and current talent. Always be trying to upgrade the overall talent of the team. Do not pass on a guy if he is the next highest guy on the board (see Joe Montana). Spend time building the board, and then stick to it. This requires you to have outside people to evaluate your team, and a group (scouts) to evaluate incoming available players. Example of why not to go BPA only: The next guy on your list BPA skill wise is a TE, but you already have 3 TE on the team that all grade out higher than him. Waste of a pick that will not play.
Last but not least...hire a play caller to advise the coaches. There are some guys out there that are much better at play calling than others, and I don't understand why you don't go out and find the best one. The coaches might have final say, but I would want to know why they deviated from the play caller and both would be sitting in front of the HC or GM or me or whomever if it isn't working. This would be part of the accountability. Team game of concept of what to do, player ability - injury, and calling would all need to be seamless teamwork. The game isn't just the players, and all need to work to the highest level or be replaced.