I agree, Dynasty should remain a player-involved mode. But that doesn't mean there can't be a coach mode similar to Campus Legend. (Coaching Legend anyone?)
It could even start out in the HS playoffs and then have the coach offered a chance to coach at a div-2 or 1 star or 2 star school depending on how well they do in the playoffs. The different schools could have different goals -- like a 1 or 2 star team would have the goal of making it to a bowl game two years in a row at which point you are offered a chance to coach a 3-4 star team. Those teams want to make it to a BCS bowl and, if successful, you can go to a 4-5 star team.
(Obviously, with the choice of staying at your current team when being offered a new job. )
I've always thought a game centered around coaching where you start out as a high school coach that must install a middle school to high school 'program' to 'build' athletes, then move to college where recruiting is the emphasis, and finally to the NFL would be ultra cool. Moving from a HS coach to a college coordinator then a college coach then a NFL coordinator, etc. And the route you take (offense/ defense) would have a major effect on your stats when you finally become an NFL coach.
Anyways, that's a whole 'nother game, but it would be interesting.