I was hoping with 4E and then Pathfinder that they would find a mechanic for damage and it's recovery that was elegant, streamlined, provide verisimilitude and would work well in a game. A tall order I suppose. While I'm enjoying what both of the previous are presenting, I'm still left waiting on this gaming nirvana I have in my head. I suppose it's impossible otherwise surely someone would have come up with it.
I think it is a tall order, for a few reasons.
Capacity to fight has at least two components: physical well-being and mental resolve. In a fantasy world it conceivably has further components, like spiritual strength and moral strength (ie the good are objectively more able to endure than are the evil).
Purist-for-system simulationist mechanics (I'm thinking of RM, HARP, RQ, Classic Traveller) tend to focus only on physical well-being. In those games the issue of mental resolve is always up to the player. Now that has two consequences: (i) PCs are always insanely brave; (ii) certain situations, like a PC collapsing due to lack of will and another PC talking that PC back into the fray, are excluded from the realm of game mechanics.
Some versions of Rolemaster do have a mechanism for spiritual damage, namely, life essence. I'll come back to that in a moment.
D&D 4e uses hit points to straddle three things, I think: physical well-being, spiritual strength and mental resolve. This is reflected both in the sorts of things that cause damage (eg both weapons, and a Deathlock Wight's horrific visage), and the various methods of healing (eg both clerics and warlords). The game mechanics don't attempt to distinguish them. This means that any given wound is apt to be narrated in multiple ways, and any given event of healing is apt to be narrated in multiple ways, and the consequence is what some players at least (eg Raven Crowking) find objectionable: PCs with real wounds (narrated as such) coming back into the fight after hardening their mental resolve (typical narration of warlord healing).
You could try and separate the physical, the mental and the spiritual each into a separate hit point pool. And then you could separate healing effects into different categories. Rolemaster does this, by separating Life Essence loss (caused by Undead) from physical injury. The net upshot, however, is that the mechanics become more complex and the game more dangerous unless the PCs have access to both sorts of healing. If this were done in 4e, it would undermine the design goal of "No need for a cleric, because any leader can do that job."
You also need to design all attacks in such a way as to make it clear what sort of damage they do. And this then puts mechanical limits on narration which might sometimes be felt as restricting (eg if my sword blow deals physical damage but not mental damage to the gobliln, then I have to describe the goblin as hurt but can't describe it as cowed - this is different from 4e as it currently stands, where 0 hit points can be narrated in a wide variety of ways), and takes us back to a mechanical need to distinguish real damage from various forms of morale-sapping subdual damage (as existed in 1st ed AD&D).
One non-4e game that fully integrates the various components of capacity to fight into a single unified mechanic for resolving conflicts is HeroWars/Quest. And in that system there is no easy correlation between the mechanics and the ingame state, as I indicated in an earlier post. 4e's hp and healing surge rules, and the narrative techniques that they require, resemble it in certain respects (though I think it's fair to say that the spiritual and moral components loom larger in HeroWars than in 4e).
So I guess the upshot of this discussion is that it is very hard to have a hit-point system that (i) is easily applied in a simulationist fashion, and (ii) brings the physical, the mental, the spiritual (and potentially the moral) components of capacity to fight under the ambit of the action resolution mechanics, and (iii) doesn't multiply mechanical subsystems, thus increasing complexity and making every sort of healer a necessity for the PCs, and (iv) permits an adequate degree of flexibility in narration.
On the other hand, if you're looking for a system in which hit points and other damage mechanics only correlate to physical injury, and therefore in which healing magic is the only way of quick recovery from injury, and which also incorporates a Fate Point mechanic to prevent PCs getting caught up in an ineluctable death spiral, then I suggest that you have a look at HARP (the quickstart rules are available
here as a free download). If you wanted to, you could even give the Fate Point rules a simulationist reading, and treat them as representative of the mental/spritual/moral component (in this case, you might want to slightly vary the way in which they are earned).
