Day/night cycles are already an incredible workload for just one, somewhat big, map. Considering the fact that this game is going to be absolutely huge, with a lot of different places to visit, implementing day/night cycles is a whole lot of work for something that's not really important to the gameplay.
It is of outmost importance, bandits , vampire's and ghost show up at night, Vampire's get huge buffs while at nigh. Nights from tactical perspective are of outmost importance as shadows and the darkness make it much harder to hit and see you for sneaking past. Even for RP and Infiltraten nights are of outmost importance. Weather effects are also need and the benefits and drawbacks of rain and thunder
The only reason why they don't do it its because they want force that crappy under dark and surface world in one map thing. To bad a loading screen for the under dark and surface world will be necessary to keep them separated as apparently is to hard for the devs cant be bothered to do there programing job. Oh boi let us show two absolutely different environments together one of eternal darknes and one of eternal light, nobody will ever notice that its not raining never gets dark. I am sorry but this utter terrible game design. Only because nobody could figure out how to make multiplier related loading screens and mechanics for different biomes and environments.
Drop the MP part or over work it I dont care about loading screens, they are welcome bathroom brake.