The issue comes down to where the line is for separate options. You're not exactly playing "Core Rules" without the exhaustion mechanic in place. You are tipping the balance of difficulty because you can perform any actions you want for as long as you want without the threat of exhaustion.
If exhaustion is toggleable in any difficulty, what other mechanics would be able to be switched on and off? Idk, but in BG2, if I used the haste spell twice before resting I became exhausted. That's just the way D&D rules work.
Don't worry, by the looks of things now, BG 3 will have so little to do with D&D core mechanics that it won't matter anyway. I say we also remove spells slots and make fighters hit like a truck for balance reasons and call it a day at this rate
Seriously? A slippery slope fallacy?
Exhaustion is not some deep-seated rule that has to be in place or D&D falls apart.
Hell, we did not use it in the last world of D&D I was part of. My rogue frequently did night missions & went with the party during the day. As long as he got at least 3 hours of rest, and did not stay up the following night, the DM did not use exhaustion.
But the Barbarian still went Exhausted after raging.
That is the difference between the timed exhaustion I hate, and exhaustion due to skills.
Allowing people to pick if time exhaustion (forced camping) is on or off won't unravel the game or cause D&D to implode like a dying star.
It should be an option, because many people, like myself, don't like stopping every 5-10 minutes to camp for no reason other than 'time passed'.
I get camping to get HP & spells per day back. Those ARE mechanics upon which a game needs to be balanced.
Camping because 5 RL minutes passed is boring, to me.
So stop with this 'Where will it end!?' nonsense. It's false.