Maybe the lack of day/night cycle is the result of the choice to enable the party to split up and do things in different parts of the world. I seem to remember Larian touting this as a great feature when EA came out. I don't think it is used much though. Some partymembers exploring thje goblin camp while others are in the grove, for instance. Anyway, adding continuous time to this feature would make synchronization of the separate groups quite problematic.
Honestly, I expect that a lot of BG III's shortcomings are the result of their approach to multiplayer.
ex1: not freezing gameplay for other players when one is in dialogue naturally leads to the mechanic where you can switch characters and screw around/pickpocket/set up an enemy boss for a 1-turn kill while they are stuck in dialogue. (something Larian has embraced as a 'feature)
ex2: the way combat works in a turn based bubble while the rest of he world is still real-time (which leads to all sorts of jank when additional enemies wander into combat (or anything involving stealth, really). which inevitably results in the initiative mechanics screwing you over and losing turns on half your party.
Additionally, the hyper-condensed 'themepark' maps make a lot more sense if you consider how their multiplayer works with the split parties. They want everyone on as few maps as possible.
