That isn't neutral though. On a scale of "Impossible to kill the PCs" to "The PCs die from a light breeze" you are choosing "PCs die to one sword strike in the right place". It might be the "default" because it's the one people are already familiar with, but it isn't "neutral". To be neutral, you'd need to write it in such a way that the game doesn't even decide how easily anyone dies, it just lets each DM decide on their own. It would be the only way to stay completely neutral.
I think you answered your own question, and I do agree with this perspective. Ideally, this would have been manifested with the sort of "dials" originally proposed for 5e. I think the appropriate method for writing the game would be to describe the real world and then clearly explain how to adjust key parameters in order to change the tone to fit one's needs. Perfectly neutral? No. But I don't think it gets any more neutral than that.
But the laws of physics say that someone's skin would have to be made out of stone in order to be able to survive the kind of damage that most D&D characters take. The laws of physics say that if someone's skin was made out of stone they wouldn't be able to move.
I think that's a pretty gross overstatement. I don't narrate damage as metal blades bouncing off a fighter's stone skin. The point I'm getting at is that as-is, damage is a nebulous consolidation of factors (including physical harm and also some combination of fatigue/skill/luck, and who knows what else). I think it would be better to have a clear mechanical representation of when a character is physically harmed, and then have other mechanics for other things.
I don't think the point of a health system should be to reduplicate the "it's just a flesh wound" scene from Monty Python.
There is no fate or luck in the real laws of physics so no one could survive because of those reasons if your rules used the laws of physics.
Well, that's pretty debatable, isn't it (though I think I agree, I suspect the majority of the world does not)? But there's also no DM here in real life. As constructed, D&D postulates a set of rules, and a DM that operates outside of those rules, which is why he can manipulate them to decide character creation parameters, say when and how mechanics are engaged, and apply changes to them to reflect circumstances.
To say that the rules are a simulation engine is not to say that your individual game must be. Quite the contrary. I'm saying that the rules should clearly serve one and only one purpose, and the DM should take care of the rest. The amount by which the DM chooses to alter, subvert, or ignore those laws of physics/rules of the game can vary according to an individual group's tastes, which is why I'm calling this "neutral".
And indeed, the d20 constellation of games is not bad at all at doing this. The tone of a D&D 3e game is substantially different than of a Modern, CoC d20, Star Wars, or other d20 game. Yet, they're all using fundamentally the same mechanics (d20 + modifiers vs DC, ability scores, skills, feats etc.). And even two D&D games can be quite different in style.
In a game based on the real laws of physics it would mean that you could not gain hitpoints or survive any well placed attack on you since that the way real skin, muscles and organs work. There would be no valid excuse for surviving and it would prevent all playstyles that want PCs to survive more than one attack.
Again, this is an exaggeration. Clearly, you have not worked at a military hospital (I have). Sometimes people do survive significant wounds and keep going; the human body changes dramatically in life or death circumstances. Other times, they don't. However, I still think that as above, it's not difficult to "dial up" (or down) durability, lethality, and the level of challenge the characters face if the game is written to do that.
I think the original bit above about needing to write the game so that these parameters have defaults, but the defaults are not assumed, is important. To some extent, D&D does this already. For example, 3e has a default array for minor characters, and a standard array for "heroic" characters. It's clear that those are defaults, however I think it's fair to say that the vast majority of characters are not built with those numbers. There's no reason the same logic can't be spread around.
In real life "True Heroism" is impossible.
See, [MENTION=11821]Obryn[/MENTION] thought it was unfair of me to even suggest that. But apparently not.
To me, heroism involves running into a room filled with 20 armed thugs and defeating them all without a scratch. In real life no one does that. The laws of physics prevent it. Only in action movies and our imagination.
In real life, the 20 people gang up on even the best fighter on the planet and beat him up. Or they kill him with one bullet that is impossible to block or dodge.
There's no reason why various law of physics mechanics can't be used to create such a scenario. However, I don't think presenting that as the default would be very "neutral" at all. Do you?
To me, that sounds like a high level fighter walking into a room of low-level mooks, or a demigod of legend walking into a room of normal humans. It does not sound like one normal human walking into a room of other normal humans. If you want that, I think it falls to your DM to create player characters that are well outside the norm of what a typical person is, which certainly is something that most people do to some extent. I've never had any trouble creating those sorts of experiences even using very "gritty" d20 mods, but I hardly think that a new player picking up the game out of the box should get that outcome by default.
The problem is that Fate IS a style of D&D...if we define D&D as a Medieval Fantasy Game with Elves, Dwarves, Dragons, Magic, and High Adventure. Which is about the only thing all the editions of D&D have in common.
Within that framework there are nearly infinite permutations of rules that will still qualify as D&D(IMHO) but will have completely different playstyles. Fate fully qualifies as one of those permutations. Though, it's not the one I'd pick since it is a little too far out of my playstyle.
I can play D&D with Hero System, GURPS, Palladium Fantasy, Fate, 13th Age, and likely a number of other games. D&D just gets to be D&D because it is made by WOTC.
Well, that's an interesting take on it. If you want to define D&D as anything of a constellation of games that can recreate certain fantasy tropes, that's fine. Those games are fundamentally different however, and I hardly think that one published game could ever split the differences between them. So in that sense, I think many other people posting to this thread have agreed that neutrality is simply impossible.