D/N is so essential and would improve the game even if it was binary.
Right. That's what I meant. They could literally do the most basic, binary system (i.e. dusk/dawn mini-video pops up, like in BG1, no dynamic light change required, a new darker/lighter version of the map is loaded, most NPC disappear/appear in their bed at night, stores are closed) and no matter how bare-boned, it would still add immensely to the believability of the game world. Not to mention it would open a lot of opportunities for quest design, rest system, fatigue, exhaustion, etc.
It's fairly jarring that a feature that was considered basic in most CRPGs since Ultima and co. is now dismissed as "too expensive and unnecessary" in a game with an overall budget that probably dwarfs the almost totality of the classics (and several current competitors) combined.