To my knowledge not thoroughly. I can only offer anecdotal evidence that it works properly. I've seen or heard nothing to indicate that it doesn't function properly though. If it doesn't, then the solution is to tune it so that it does.
As for morale and the impact of signing players to contract, that should be determined by the front end coaching scheme imo. If I set my RE to be a speed rusher, speed rushers would be more inclined to join my team and run stopping REs would not be as thrilled. Then if the speed rusher isn't getting sacks he will start to lose morale.
For AI coaches I remember in NCAA there was a slider for each coach for playing the run vs the pass. I was never 100% sure what this influenced, but I would like to see it return in Madden and influence play calling and potential coaching adjustments.