When the coaching tree comes up
I don't see any reference to regression in the coaching tree when it is mentioned. What if coaches ever experience a decline or loss of capabilities they possess? What is the rationale to ever move on from a fully-developed head coach?
I love to run these mockups into a scenarios from the real world. What would have stopped the Eagles to have stayed away to Andy Reid? What effect does Jason Garret going from head coach to OC impact his capabilities?
I'm ok with salary caps and changing coaches at lower levels around to accommodate the development of specific players, but is there any reason to change your head coach once you've "maxed up" on his progress?
I believe that you should want coaches to fall back at some point , but I'm not convinced that it'd be essential. Based on what I've laid out here, fully developed, fourth-tier coaches would be uncommon and at any moment there would be just few coaches in all of the league.
Most coaches be in and would have a ceiling in the top three tiers. Except for Reid and others, coaches like Belichick, Tomlin, Harbaugh and others "tier-four" coaches are all stuck in the same position for an extended period of time. I believe that in Reid's Reid situation, it could be a situation where a bad season or a series of seasons poor performance could affect the team's morale and team chemistry to the point that you may want to get rid of Reid to bring balance back to your team, or so it's said. If you're fortunate enough to be able to have or acquire a player such as that, you should not be getting rid of him. If the coach leaves, it'll be more about external factors like chemistry and morale or possibly the other team will come in to steal him instead of their ability.
This Garrett question is a great one, and in terms of the differences among HC and OC I don't believe it's going to have that much impact on his capabilities. It is possible to do something like the perk was something that affects all players but it could only work if he was HC as well.
And if he were an OC then the perk could only be used on the offensive aspect of the ball, or perhaps not be effective at all. I believe that the only way to have more impact on the player's abilities is when your coach was such as Garrett who enjoyed QB benefits in the role of your coach for RB, or some other thing. In that scenario, it would be sensible to deactivate the QB perk removed because he would not be directly working with the QBs.
What I envision for coach progression/regression would look a lot different than what you see happen with players. Because coaches' careers are an extended timeframe so the progress is likely to be slower and less frequent, and there would be many coaches who don't even make any progress and would continue to spend their entire time as coach of positions. I think that going this way will make it simpler to manage and maintain balance. One thing you'll need to avoid is getting several seasons and having half the team with Belichick-level coaches and top-tier coordinators as position coaches , because there's an abundance of excellent coaches.