I wrote the following as a comment there, but I'll repeat it here:
If hit points don't represent wounds, but represent your ability to turn a serious blow into a lesser blow or shrug off minor damage, then hit point loss doesn't represent serious injury but is more a form of combat awareness and stamina.
This means two things. First, that dropping to zero hit points means that a strike got through your defenses and caused a serious wound. Second, that most magical healing isn't really healing wounds (at least not major ones), but is instead refreshing the character's stamina and battle awareness.
So, when you drop to zero hit points, you're wounded, staggered, and bleeding out. You should also have to make a save to stay conscious.
Magical healing should stabilize you, and give you back hit points, but not remove your wounds.
I don't know if negative hit points are the best way to represent wounds and bleeding or not. But for the sake of discussion I'll use them.
If you take six points of negative hit point damage and are healed for twelve points, then you should have twelve hit points AND six points of negative damage. You should probably also still be staggered unless you take a feat that lets you ignore wounds.
Only natural recovery or very powerful magic should be able to heal negative hit point damage.
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Now I want to add just bit to what I wrote above.
What I wrote is my preference, and I think that it opens up a lot of options as to what you can do with wounds, the staggered condition, and damage types. If a sword drops you, you've been impaled. A mace has broken your bones. A fireball has burned your flesh.
It also provides a more consistent opportunity for a character to be staggered. To fight on even when you can barely move and you're bleeding to death. Sure, this might require a save every round to stay conscious, but it's cool.
Still, the biggest advantage with what I posted above is that it can be modular.
- Pulp Rules: If your group doesn't want to deal with long-term wounds, then negative hit points simply disappear with any magical healing.
- Lethal Rules: If you want something more lethal, add a injury chart with some lethal options.
- Grittier Rules: If you want wounds to happen more regularly, add a massive damage save.