@Rhobar121 I agree that those are potential problems. Incorporating a fatigue (or other long-rest limit) system would require more work for the design team (not necessarily a bad thing if it results in a better game).
However, most of this game can be done in different orderings. Larian doesn't have to exactly tune every encounter. If the player doesn't have enough resources to fight the Minotaurs, then they can go another path to find easier enemiese: 1.) jumping to another region of the underdark, bypassing the minotaurs 2.) going back to the overworld and exploring the Hag's lair, Waukeem's Rest, the Inn with those Paladins, the Creche, the cursed route to the Tower, or more.
Something your points don't fix is the current balance of short-vs-long rest classes. IF Larian wants every fight to be taken at max or near-max strength after a long rest, then they should also adjust the classes to strengthen short-rest classes and/or weaken long-rest classes. Given the options of Larian either implementing a long rest limit or making further changes to the classes, I'd prefer the former.
That won't address anything, most of these end up in pretty tough fights too. So you'd wind up clearing all the easy stuff everywhere, and then nothing but hard stuff to do, and no way to rest between them. I wouldn't call that particularly balanced either.