That's true. Even so, I remember nighttime fondly in Ultima. I wasn't as annoyed shops were closed because it was expected and it was neat to see people going about their evening routines. Plus, Larian could add a "pass time" function in case you wanted to rest until dawn so the markets were open.
Day and Night adds more uses for clocks, watches, and personal light sources as well as the opportunity for quests and other plot devices which happen only at night.
They might need to put night watchmen on patrol in Cyseal, though, or stealing all the stuff laying around would be too easy!
Maybe they can add it in an expansion. I'd imagine the change would be too involved to implement for the current game.
After all this isn't The SIMS: Late Night
