This just isn't true. Most of the supernatural powers (Blink, Dark Vision, Bend Time, Possession, Windblast, Agility) were non-lethal. It was only the rat swarm and turn-bodies-to-ash one you'd miss out on, and all the weapons and gadgets had lethal and non-lethal variants.
This is the game that turned non-lethal assassinations into almost mini-missions of their own, figuring out the sequence of events necessary to deal with all your main targets without having to kill them. Things like eavesdropping on guards and reading books to find out you could brand the High Overseer as a heretic, turning him into an outcast. Or the whole investigation at the fancy dress ball, talking to all the guests to work out which of the three identically-dressed sisters is your target, and then convincing her to follow you out to the sewers to be abducted. As opposed to the lethal option of "just stab'em"; if anything there was more attention paid to to non-lethal side of gameplay.
Maybe you misunderstood me, I am mainly talking about powers that you can use for "combat."
Things like:
Devouring Swarm
Wind blast (the upgraded version)
Blood Thirsty
Shadow Kill
Are all powers that you can't really use if you want to play for the good ending.
Meanwhile, what powers (for combat use) are there?
There's bend time....and the first version of Windblast, that's about it.
Then you had the weapons, sword? nades? ranged?
Where's the blackjack? brass knuckles? Sleeping darts?
Thief/Deus Ex (the first one) and Hitman are better at this then Dishonored imo.
You had far more gameplay choices if you didn't care about getting the good ending.
I'm not saying that it wasn't nice to have choices in how you played and have choices that affected the ending in moral ways, I'm just saying the powers and tools they give you far favored the "bad" apporache over the good.