I think the idea of a largely cosmetic day/night cycle (which should alter the lighting and stealth mechanics) isn't a bad one. It would be a simpler idea of limiting long rests than my proposed mechanic.
At very least it would work at the most basic level and it would set the groundwork to endorse a lot of modding in that sense.
Also, it would spare Larian from the issue of "having to add way more beds into the game world". Not that many would care that much, honestly.
Still, when you really think about it, it's a bit jarring that some standards set 30 years ago by Ultima VII in terms of scheduling and dynamic behavior have yet to be matched in any modern production.
Also, again, I'd like to mention that fire looks great at night and Larian is really missing out on fire if they miss out on fire at night. Just gonna leave that here...
Already said it in the other more generic "mega-thread", but imagine the disappointment of finally reaching Baldur's Gate, start exploring its quartiers and streets... and outside of a (possible) handful of scripted events being forced to roam the city only in midday light.
Without experiencing the scenery at night, without all the street lights turned on, with no "nocturnal street encounter" whatsoever, etc.
I have almost a hard time understanding people (admittedly not many) who keep dismissing this sort of "flavor" as something they don't care about, frankly.
And this is without going too much into the potential impact on the mechanical side of things.
