I don't think you have a great shot at getting better during the games. I'd very much dislike being a starting RB or QB with this philosophy. Knowing that I can get blown up at any moment so this guy can develop.
Let him be a wedge guy on punt and kick off. If he's got the fire it'll show there. Go ahead and blow out an FCS team and let him play the 2nd half.
I don't understand not starting your best team. It seems like this puts winning 2nd to player development.
NFL size does not equal NFL talent.