Its quite a simple problem having nothing to do with <engine limitations> (give me a break, this isn't a indie studio...) more to do with TIME standing still itself in the game. There are no calendars, dates and any sort of time flow withing maps. Time is showed by just switching map zones or camping. Easy way out to a somewhat complicated problem, which does not have to be that complicated...
But to Larian it seems that day/nights MUST BE <next gen> dynamic and be like the Witcher3 and Elder scrolls games...(including its baggage of NPC scheduling AI problems), and will not accept anything less. So sadly its a big NG for them. That would indeed be a huge time sink. They do not want to settle with a 6/10 score half baked day/night system. They aim for a 9/10 10/10.
My interpretation of whats going on anyways...
I feel, again, that time is just a fake problem. Except for some realism unless software companies start to put time limits to the quest both principal (in Daggerfall it was amusing how you could explore all the frigging huge map and the main quest still be there) and side ones time passing just becomes a decorative item. I play Eso and there you have day and night, and rain, and sun, but monsters are the same, you can explore the full map without finishing any quest (but with days passing) and none of those quests become botched (hell, with some characters I decided to dithc the main quest and move to the new ones opened with the dlc released). Another problem is that programmers should take better account of consequences and how they influence the world (for example: why can't the Tav inform the hih druid that the woman he nominated is conspiring with drak druids? Or why the druids in the cove don't get the news that you freed the high druid or why, if you encouter auntie in the druid's cave when you encouter her she acts like you're a stranger, or the tav's dialogues doesn't aknowledge that you knew her? In Skyrim the must laughing situation was in the city were the magic shcool was: even after the character become the archmage in town dialogues still settled as if you were a newcomer without affiliation to the school)
I would love some signs of time passing instead of a time freezed (partially because the camp rests states that you end the day and there are night cut scenes) in a due moment even if for cosmetic reasons but nevertheless I think that to seriously manage time the video games production philosophy should pass a revolution, that would involve players too are players (specially occasional ones) ready to a game were the result of the main quest can change based on how much time they used to complete it, would they manage to accept botched side quests because of bad player time management? and so on.. ...
