While allowing the party to be split up, with some in real time and some in turn based combat, does cause issues with syncing a day/night cycle, that isn't really critical. The main problem is just the added complexity for doing a day/night cycle properly, on top of already complex scripting and narrative. With level design every NPC needs a place to go at night, those places need contents, etc.
And Larian would be the very first developer who does this? Especially sad when you can play as a drow but you dont have dsy/night cycle. Even BG had this and it's 20 years old. Some statements really sound like you didn't even try to do something else than your last game. Also audio in different languages. Tons of games have it, but larian of course not
