(Let me qualify this post by indicating that this is my response to the thread--not necessarily to anything Larian has officially said about a day/night cycle. I would have thought day/night would be a a given seeing as how it was asked for & promised in the first game--but not delivered, for reasons that should not at all apply to DOS2, imo.)
I don't buy the idea that day/night is somehow so difficult that it's beyond the ability of Larian to do--development of DOS2 has just begun--thus the "it has to be built into the game from the ground up so we can't just add it" mantra won't work here...as it was used to explain why it couldn't be done in DOS even though it was supposedly a stretch goal for that game that was promised by the developers (but never met.)
In the DOS2 Kickstarter Larian raised a multiple of the dollar goal they asked for--so if Larian needs "more hires" to do day/night then that should happen (which seems silly to me--the same guys that can do day can also do night--why not? It might take longer in development--but that's it.)
And also the idea that a night cycle would involve all new quest lines and all new schedules for NPCs and implementing that would become a terrific burden--well, it doesn't have to be so complex--just like in real life. When the sun goes down we don't stop pursuing our goals in life, do we?...;) Nope, those goals go right into the next day, don't they? They do not fundamentally change. The sun going down doesn't have to present an unsolvable dilemma from the development side, good grief. Anyone remember the old Might & Magic (not Heroes) rpg's of 25-30 years ago? Well, Day/Night was worked into those games even though the developer of those games didn't have peanuts to work with as far as money or personnel goes in comparison with Larian's resources for DOS2.
I can only think of one reason why Larian would resist putting in a day/night cycle and I have to say it's disappointing--and that is that Larian wants to reuse a lot of the assets created in DOS in DOS2, and that wouldn't be possible with a different engine and a day-night cycle because all of the night-time assets would have to be created fresh. So? What's so weird about creating a bunch of fresh assets for DOS2--the people contributing to the game surely expect that, and rightfully so.
Bottom line is that day/night is not the boogeyman Larian keeps saying it is--it's been done before in other games with a fraction of Larian's development money & personnel, and at a time when the general technology for game development was not nearly so robust as it is today! Larian is one hell of a talented company--this insistence that day/night is beyond them seems ludicrous, imo.
