And yet, "Shroedingers Wounds", the inability even for the DM to know if a wound is physical or not, because now people can be healed by shouting at them instead of magic, was and still is a common complain with 4E.
This has been countered and explained dozens of times. It is not a grievous wound until it reduces you to 0 HP or less. Anything else is bruises, scratches and fatigue. And for the record, while people can't
heal wounds by being inspired, people have been known to ignore some serious injuries, staying up by pure adrenaline and willpower. So yes, a warlord who uses inspiration to "heal" HP damage can, in fact, get someone standing again after they've taken a wound (also known as "had their HP reduced to 0 or less"). Once the battle is over, first aid can treat wounds well enough that, while they're not "healed", they are no longer life-threatening, and the person can keep on fighting.
If you really want to model wounds more accurately, I could see replacing negative HP with Wounds. If an attack would take you below 0 HP, then you are reduced to 0 HP, fall unconscious and suffer a Wound. While unconscious, you must check every round to avoid taking another Wound. Even if you are healed and wake up, the Wounds stay. Three Wounds and you're dead. Wounds heal at the rate of one per day assuming basic first-aid; the wound isn't completely gone, but you've recovered enough that it won't hamper you while it finishes healing.
This works to combine classic HP and the ability to model actual wounds. It also serves as a long-term damage counter; you may be at full health, but if you have two Wounds, you're still gonna have to be very careful to avoid dying. It also allows a few interesting mechanics to help cover other issues people have, as well; you may not have to worry about "Save or Die" spells, but "Save or take a Wound" spells may show up on dangerous enemies. You can have tons of healing abilities to recover HP, and from tons of sources... but only a Cleric can cast the spell that heals Wounds instantly. Unavoidable damage (falling from a great height, or being crushed by a closing wall trap) could cause outright wounds instead of HP damage. If you up the number of sources of Wounds like that, though, you may want to include an option for more Wounds. Fighters and Dwarves can each take an additional Wound before dying, for example; a Dwarven Fighter is
great at not dying.
You'll note how this is still abstract, easy-to-run, and quick to play in-game.
And it took me about ten seconds to think up.