So, in a hit point based gaming system, the HP dictate player morale.
I like to reverse-engineer this fact. Hit points are also character morale. If you play that zero HP or below is a serious physical injury possibly killing you, then any damage prior to that is the wearing down of confidence by near misses and glancing blows. And, as long as you have enough confidence, you just cannot be killed. Welcome to a heroic universe.
- Failure to regain HP losses when resting in less than optimal conditions makes sense. So does losing HP for staying in such adverse conditions. Inns where you can't bling out to the tune of X Gold Pieces/Level are just not going to restore your pampered morale!
- Magical fear can be modeled - and created in players - by a process of slow but nonlethal wearing down of hit points when in the presence of a terrifying creature or area.
- Clerics don't so much lay on hands most of the time, as restore confidence and will. This might be an argument for same-religion healing bonuses. If going this route there also needs to be a way they can heal serious injuries.
- Zero hit points might be "unconscious" but might also be "whipped and weary."
- Healing surges make total sense!!!! (Okay, forget I said that) How about ... bards can cast area effect cure spells?