Although admittedly, I am a big fan of XCOM2, and I do also like the timer on that game which matches with the stress of an alien invasion, and it really worked in that game. I really don't see any kind of timer working in this game. They are two totally different types of game. Not to mention, we have no idea what is going to transpire after the starter area (the EA).
Considering that originally (as quoted by a poster above) Larian actually increased the number of short rests to streamline adventuring time, I really don't see them just doing a reverse course, and putting some kind of time restraint or any other mechanic that would limit the amount of time you can go to camp for a full rest now. They have never had a day/night cycle, maybe that is an engine limitation, I don't know. But it would be cool to have some "night missions" when we reach Baldur's Gate. I am assuming even if this was done, it would be a loaded instance of the quest area, and not open world.