As with most coach adjustments i would like the players to have a corresponding trait of how they tend to play. Some already do and balanced should make them play to their trait. For instance at balanced the secondary players that have the aggressive trait should play aggressive and conservative should play conservative.
Constantly asking players to play against their trait should affect morale/chemistry/confidence. Some defensive linemen are aggresive pass rushers by nature and are much more likely to cheat on their run stopping duties to go after the qb. I would love to see a trait like that in the game and if you constantly tell that guy to be conservative he would get mad and be hard to resign. These things woud make cfm more enjoyable and make in game coach adjustments mean something in that i lf you just set your oline to aggressive the whole game it would make some players mad. Each player should have a trait in my exaple of either more likely to read run, pass or balanced. Like you said it has to be a game of percentages. The coach adjustment woud be similar to the coach or defensive captain telling a rookie to nite bite on play action or watch out for the draw. I also thknk screens should be considered runs for this adjustment.