Hussar
Legend
Wow, longest thread I have EVER started. Yay me. And, from what I've seen, amazingly civil as well. Cookies for everyone. 
I admit, I've skipped the past few pages, so, if I'm repeating stuff, bear with me.
All this discussion on the relative levels of abstraction of hit points misses a better question in my opinion. It's quibbling really - does it really matter that one is more abstract than the other when both are abstract in the first place?
But, the better question in my mind is: Why hit points at all? There are all sorts of mechanics for determining combat effects. Yet D&D's ablative hit points remains absolutely king in nearly every sort of game, both RPG and computer games. The overwhelming majority of games which feature some sort of damage mechanic, from something like Diablo, to Mortal Kombat have exactly the same mechanics for hit points as D&D. You're fine, you're fine, you're fine, you're dead.
And computers could easily handle the gruntwork that makes systems like GURPS combat fairly painful at the table. But they don't. And I think I know why. Raven Crowking WAY back in the thread talked about how Gygax, when he created hit points, said that he went as far as he could with simulation without hurting gameplay. ((Paraphrasing))
Think about the priorities there. What's the most important thing there? Gameplay. How it works at the table. While there are people who enjoy spending hours running through every second of a combat, I'm going to guess that most people don't. And, a countdown mechanic is probably the most intuitive one you can find.
Just about every game where you can be knocked out, be it Poker or Monopoly, has the same thing. You have a limited resource, that can be replenished, but when it's gone, you're out of the game. There are so many games that work like this.
But, moving on from hit points for a second, let's look at how another mechanic developed over time based pretty much entirely on gameplay: Initiative. AD&D 1e initiative rules are... well... let's just say they're perhaps a little overcomplicated. One of the big changes in 2e was streamlining initiative rules. You go from d6 with all sorts of modifiers based on a large number of sources, to a d10 + speed (either spell casting time or weapon speed) - Dex bonus. Reroll every round.
Then 3e steps up and streamlines it even further. D20+dex rolled once. But, they retained a few earlier concepts and so we had focusing things like that. 3.5 stepped even further down the line and streamlined it so that moving up in initiative order is pretty difficult.
Purely done for gameplay reasons. Mechanically, any sort of initiative mechanics work. AD&D 1e mechanics worked. But, they were too complicated and confusing. That hurt table play. So, it get's slimmed down. Then slimmed down further. And then further still.
That's why I feel that game first mechanics are better. Placing the first priority on at the table play is the most important consideration for any mechanic.

I admit, I've skipped the past few pages, so, if I'm repeating stuff, bear with me.
All this discussion on the relative levels of abstraction of hit points misses a better question in my opinion. It's quibbling really - does it really matter that one is more abstract than the other when both are abstract in the first place?
But, the better question in my mind is: Why hit points at all? There are all sorts of mechanics for determining combat effects. Yet D&D's ablative hit points remains absolutely king in nearly every sort of game, both RPG and computer games. The overwhelming majority of games which feature some sort of damage mechanic, from something like Diablo, to Mortal Kombat have exactly the same mechanics for hit points as D&D. You're fine, you're fine, you're fine, you're dead.
And computers could easily handle the gruntwork that makes systems like GURPS combat fairly painful at the table. But they don't. And I think I know why. Raven Crowking WAY back in the thread talked about how Gygax, when he created hit points, said that he went as far as he could with simulation without hurting gameplay. ((Paraphrasing))
Think about the priorities there. What's the most important thing there? Gameplay. How it works at the table. While there are people who enjoy spending hours running through every second of a combat, I'm going to guess that most people don't. And, a countdown mechanic is probably the most intuitive one you can find.
Just about every game where you can be knocked out, be it Poker or Monopoly, has the same thing. You have a limited resource, that can be replenished, but when it's gone, you're out of the game. There are so many games that work like this.
But, moving on from hit points for a second, let's look at how another mechanic developed over time based pretty much entirely on gameplay: Initiative. AD&D 1e initiative rules are... well... let's just say they're perhaps a little overcomplicated. One of the big changes in 2e was streamlining initiative rules. You go from d6 with all sorts of modifiers based on a large number of sources, to a d10 + speed (either spell casting time or weapon speed) - Dex bonus. Reroll every round.
Then 3e steps up and streamlines it even further. D20+dex rolled once. But, they retained a few earlier concepts and so we had focusing things like that. 3.5 stepped even further down the line and streamlined it so that moving up in initiative order is pretty difficult.
Purely done for gameplay reasons. Mechanically, any sort of initiative mechanics work. AD&D 1e mechanics worked. But, they were too complicated and confusing. That hurt table play. So, it get's slimmed down. Then slimmed down further. And then further still.
That's why I feel that game first mechanics are better. Placing the first priority on at the table play is the most important consideration for any mechanic.