I feel like I'm missing something.
The game is full of powers and upgrades to give you better killing ability. Nearly all the upgrades are for weapons. For where I am in the game at least, there's not even an upgrade for sleep bolt capacity, just normal bolts. Most of the weapon upgrades are for the pistol, which is loud and lethal. Most of the gadgets are things for killing, like the mine and grenade, and even the rewire tool is often used to kill, since the easier way to turn off a light wall is just to... unplug the damn thing. And like half the abilities and enhancements are for death as well. Even the ones like Vitality aren't exactly useful in a full stealth playthrough, unless you get caught and shot at a lot. It's all very death related, and there's not a whole lot that feels useful for stealth/non-lethal.
Yet the game's level/map and story mechanics are specifically geared toward being non-lethal. Death brings more rats, more weepers, and it tells you outright from the start "You will get the bad ending if you kill a bunch of enemies." It's not even about the morality, story, or "does it make sense" aspect. Like I feel like you could argue that killing corrupt guards, weepers and thugs isn't exactly the worst thing, but that's not my issue. It feels like the game mechanically encourages you to use lethal methods and focuses on those, while also telling you that doing so is bad.
The other issue I have is that going non-lethal means: Blink around, non-lethal takedowns without any upgrades for those, and sleep darts. It cuts all the variety and half the mechanics out of the game. The sword and pistol might as well not exist for me so far. Same with mines. Grenades I can at least use as a distraction.
It's still fairly fun, but I feel like I'm playing wrong, or missing something. I was looking for stealth AND combat, and this feels like just stealth, because of how lethality is treated. I'm not even disagreeing with the design choice, but it feels kind of limiting, and like it negates half the upgrades. It's not really scratching the itch I have.