Yeah, that's the hope. Right now attempting to keep someone alive feels live window dressing that doesn't have any real impact in the game.
For all intents and purposes, a "knocked out" character remains a corpse, he never seems to "come back to life" nor is ever acknowledged as "spared".
I am pretty sure they will consequences sparing some of the NPC's at least. I do not think they would have added the ability to knock people out if they weren't planning to. But then again, it might be a ton of work to script outcomes. Maybe they are checking metrics, to see if its worth adding? Enough people sparing NPC's I mean.