Don Durito
Hero
But it's not nerfing them unless it's preventing them from taking long rests in the dungeon situations. Which it probably won't, unless they were previously able to take long rests within the dungeon. If it means they have to leave the dungeon to take a rest - than it probably doesn't really make a difference.Which is what the OP was talking about. When traveling, the frequent long rests, the casters seemed to outshine the others, but in dungeons, etc. when long rests were harder to come by, it seemed more balanced. And now the OP wants to extend the long rest to 36 hours, which with all other things consistent will nerf them, which is also why the OP said the caster players were complaining.
As far as the actual time, otherwise, yeah I agree it doesn't matter. Which is why I've posted the "adventuring day" is really just the time between long rests and has nothing to do with actual time.
I'm assuming the OP is happy with rest pacing in dungeons and isn't particularly looking to change it - it's just the inevitabilty of nightly resets during wilderness journeys that's the problem.