i have never noticed this.
I mean is this intentinal? should darkness be a factor in the game?
They put a lot of work in improving the lighting system.
Considering that there is renewed emphasis on stealth, I believe that snuffing torches out should have an effect. After all, npc sight radius could reduce according to how well-lit an area is.
And portable torches would be great.
It would add a lot of atmosphere, and be ideal for setting up ambushes.