[Varyon]

Originally Posted by Opellulo

Yeah that's the idea but there is a problem: many combat oriented systems have really poor mechanics to simulate anything that's not a way to kill your enemy.

Indeed. GURPS does have a lot of options, ranging from mundane grappling to supernatural Afflictions (and with plenty in-between, like cinematic sleep poisons), but not every game does.

Originally Posted by Opellulo

In D&D/Pathfinder the options to knockout or applying non-lethal damage are almost always class restricted and ALWAYS less efficient that going for the kill: in those Worlds choosing anything that's not reducing your opponent to 0 HP is a tactical failure.

From a narrative - and realistic - perspective, this is largely how things should be. Not going for the kill should be more difficult - you're purposefully limiting yourself to non-lethal methods. Characters don't avoid killing because it's easier to subdue than kill - they avoid killing because of the consequences of doing so (and note for some characters, "someone is no longer alive because of me" is a harsh enough consequence for them to avoid killing). There can be exceptions to this, of course - some foes are sufficiently difficult to kill you basically have to subdue them first. Even then, however, killing is often easier - if for no other reason than not being at risk of the foe later escaping.

Originally Posted by Opellulo

In many D&D (and many Videogames) instead "fight" is the only possible activity and murder = XP. It's unnerving (and quite troubling) how one of the most heinous act possible is converted in just a token for power grow. I personally find this not only plain WRONG but also extremely boring.

Yes, one needs to be careful what choices are incentivized in a game (and elsewhere). As a counter-example, consider Deus Ex: Human Revolution and Deus Ex: Mankind Divided, wherein you get bonus XP for knocking out an enemy instead of killing them, and further bonus XP for being stealthy (which in turn makes using non-lethal methods more feasible, as you aren't needing to close to melee or use a low-RoF weapon while in the middle of a firefight). Personally, I feel that's rather artificial, and favor the approach of things like Metal Gear Solid V and Death Stranding (in the former, captured foes can be converted to join your forces, and there's also a hidden "demon points" tracker that goes up when you kill people and animals, so it's ultimately best to avoid killing; in the latter, you need to take the corpse of anyone you kill to a remote disposal facility or you get a game-over when their body creates a BT that annihilates a large chunk of land).

Originally Posted by Opellulo

And Hit Points are just the embodiment of this process, in some Pathfinder games I joined they were, at best, a time optimization resource: "we cannot withstand another round so we need to thin the baddies ranks" more often than that they were just a way to sort the marching order and/or the engagement distance.

I understand who wants to play a tactical skirmish game but, frankly, it's not my cup of tea: I prefer to play a game where every choice (even combat ones) have interesting effects more than a random "roll dices and subtract numbers until you run out" game.

This is much more the case in other games than GURPS, although GURPS does have some aspects of that. Note the Conditional Injuries rules we've been discussing make HP no longer a resource like this - rather, there's an effects-based approach to wounding.