Oh man! I know how you feel on that one. I would still so much love, and I still hope for, a true Day/Night cycle for this game. Even if they just implement a simple mechanic where you can have 2 long rests a day instead of 1. Click the button and instead of End Day it is a switch from Day to Night, that's all we need. It doesn't have to be some sort of realtime clock or anything. Chances are, you're not going to adventure for 12 hours straight and slowly watch the day go by. Either you'll adventure by day or night.
But the one good thing about a true Day/Night realtime clock is you can have variations in the time of day, which was super awesome in BG1 and 2. You could be exploring a map at dawn and have it slowly transition to morning, or you could adventure at twilight and have it somewhat darker but not fully night. Those were really awesome experiences. I also loved how it might just start thunderstorming on you while you were in the middle of exploring some dark woods; like Cloakwood. It REALLY added to the experience and made the game so much more fun.
It iS called a roleplaying game for a reason. You are SUPPOSED to feel like you are in the world. That's the whole point of it. The more you are able to immerse yourself in the world, the better it is at being an RPG.