We all know that there are times when we love that HP are abstract. There are also times when the abstraction is annoying. Here's a suggestion for those times:
What if the rules explicitly gave the DM the choice to describe going into negative HP as EITHER going unconscious or as crippling injuries that leave the character screaming and helpless, but conscious. (Holding his guts in, feebly trying to straighten his limbs, etc.) In either case, the character can still "bleed out,"
Benefits: Allows characters to give last words, even if they hit -10. ("I'm sorry, Jim, I'm a cleric, not a miracle worker. You have a few minutes to talk with him before he slips away.")
Benefits: Allows dying players to have something to role play while the others are in combat mode.
Benefits: Optional rule that encompasses old rules, and thus is backwards compatible.
Benefits: If not treated by magical healing, it allows for past injuries that make for more flavorful characters: bones that didn't heal right from falls, ringing in the ears, horrific scarring, limps, etc. None of these would have game effects, but would rather explain existing traits: poor listen skill check, poor charisma, identifying marks, etc.