I am trying to correlate this to JCA especially some of the great backs we've had and how decisions have to be made based on their overall toughness and durability.
Ty Isaac - You know Ty was going to fumble 1/30 touches and going to be injured (minor) 1/50-60 touches, even more if he's running between the tackles. So you make educated adjustments to get him to the outside more where he he can use his great speed, not run him constantly on counters until he breaks.
JR Zw... (not going to try and spell that) - one of the toughest FB players I've ever seen. We still limited his touches by utilizing other backs to the tune of 1,000+ yards, so as to not wear him out and increase his damage received. He was also very good at LB and DB where he was used sparingly in critical situations, again to keep from wearing him out and minimize damage he received.
Mike Alstott - We all know how tough he was, but we still limited his touches by utilizing other backs, so as to not wear him out and increase his damage received. And Mike probably would have made one incredible LB, but it just didn't make sense to utilize him there, to keep from wearing him out and minimize damage he received.
What I'm saying is: you can't just max out the utilization of your studs with no regard for their chances of getting injured or worn out from over-use.
My 2 cents.