Azrael the cat
Arcane
I suspect that Deus Ex developers consciously made the KO easier to pull off because enemies will wake up any unconscious ally they see. For ranged non-lethal weapons this can be a significant tactical challenge on some maps.
Thing is, it's almost never a problem when you're KO'g an enemy in melee. This is partly because you're immediately well-placed to hide the body (c/f sniping a room with tranq darts from a covered height - either you snipe EVERYONE before any of them react to each other, which might not be possible due to the reload time, patrol routes and tendency of enemies in some rooms to cross-cover each other effectively - or you take down 1 enemy and hurry down to hide the body before another patrol comes past). But it's also the interaction of map design and gameplay - in DE:HR you're more likely to use close-range KOs in corridor-heavy maps where getting spotted isn't a big worry. The big exceptions are a few occasions (one, Alice Garden Pods being the highlight of the game, in my view) where you're ambushed or walk straight into a fuckload of enemies and if you haven't gone a combat build you need to quickly KO 1-2 enemies and hide (or jump and hide in the Alice Gardens case), and when those come up you usually don't care about enemies being woken back up (as you're high-tailing through there avoiding conflict, not trying to KO the room) so the disadvantages of the melee kill really stick out.
Thing is, it's almost never a problem when you're KO'g an enemy in melee. This is partly because you're immediately well-placed to hide the body (c/f sniping a room with tranq darts from a covered height - either you snipe EVERYONE before any of them react to each other, which might not be possible due to the reload time, patrol routes and tendency of enemies in some rooms to cross-cover each other effectively - or you take down 1 enemy and hurry down to hide the body before another patrol comes past). But it's also the interaction of map design and gameplay - in DE:HR you're more likely to use close-range KOs in corridor-heavy maps where getting spotted isn't a big worry. The big exceptions are a few occasions (one, Alice Garden Pods being the highlight of the game, in my view) where you're ambushed or walk straight into a fuckload of enemies and if you haven't gone a combat build you need to quickly KO 1-2 enemies and hide (or jump and hide in the Alice Gardens case), and when those come up you usually don't care about enemies being woken back up (as you're high-tailing through there avoiding conflict, not trying to KO the room) so the disadvantages of the melee kill really stick out.