but unless you overused haste (love this spell <3)
If going inside an inn to cast it just to run faster to the edge of the map is overusing then I guess I'm overusing it xD ( #No fast travel)
I have to say, I hope: 1) They do implement some kind of exhaustion system to sygnalize the rest is required. I finished the game not knowing there is romance in it. I got the mindflayer powers nearly before the outcome of the game.
2) Sleep is balanced and straight up forbidden before a certain point(Maybe based on difficulty?). That would require some kind of time management system or another way to calculate it but right now ....well, the most optimal way is to rest after every fight. By not doing so I'm playing in a sub-optimal way. I forced myself to do so, cause i knew those poor mobs weren't ready for this. And we don't have high level spells yet! But yeah, either rests get balanced either we will end up with more hp for the sake of more hp on higher difficulties :|
Concerning 2) you could still fast travel and then rest there, which would replenish resources and then travel back. The only thing added by this would be the times it wastes. And BG3 already wastes a lot of my playtime with poor movement, long loading times, a rather slow turn-based combat and the resting how it is implemented. Well not waste in some cases, but it takes a lot of time and time economy is very subpar currently. Technically you could argue that resting in certain areas might not be advisable (like in a dungeon), but still a necessity. The Fellowship rested in Moria, for example, because they had to. You could make the same case for many dungeons in RPGs.
However it is true that resting is a essential concept in the PnP experience. You could argue though that it's necessity and reason to exist in a video game is diminished. Hence it's soft implementation in BG2 or PoE (and especially PoE2). So far, BG3 forces resting for gameplay and narrative reasons. I can not see them changing that, most interactions would have to happen in the real world then. So limiting resting would not make much sense either, because you would make the game harder and players would miss story bits. It is a conundrum, for sure. I am not even sure, they went with a worse mechanic than others, just with a rather cumbersome in an already very slow game.
