I have to disagree with the day/night cycles. I'm not against the idea, but it really is "too much work". And you also have to think about the game implications. Is it just a visual thing? Or does it affect gameplay? If it's a visual thing, it wouldn't be that hard, but you'd have to ask yourself if it's worth it. You can't even see the sky most of the time. If it's a gameplay thing and it affects skills, spells, combat or NPC behaviors, then this really should've been planned from the beginning. I think it's far too late for anything like that this late into development.

Perhaps a toggle button for the D/N cycle would be an idea and they could give some stealth advantages and increase the amount of enemies during the night. But, would the NPCs change their behaviors? Would they go to bed or stay outside all the time? I don't know, it just doesn't seem feasible to me and it doesn't seem like Larian actually wanted to implement this feature during the planning stages. They've probably shifted their resources into making cutscenes and increasing the overall quality of the game which I totally agree with. Perhaps they could work on the D/N cycles for their next installment. I'm assuming they'll make quite a bit of revenue with this game and will have a lot of re-usable assets ready so they can shift their focus towards new features.