Neverwinter Nights 2: Mask Of The Betrayer interview

"Initially, there was talk about having death be more permanent than it was in NWN2, but there were concerns about what would have to change in gameplay and in the engine and whether that was worth it. So, the focus moved to how to make death still matter to the player.

"This turned into an entirely new mechanic that makes time much more critical to the player. Certain areas change as day goes to night and while you can rest in most places, there are going to be other things to consider as you use up that time." Which implies that the days when you just camp every ten feet down a dungeon to stay at full power may be behind us.