Mercule
Adventurer
Well, acting inhuman is also a problem for verisimilitude.It only takes eight hours of rest for the mage to get his spells back. I always assumed adventurers work at night as well as day. When I did overland travel or daily time calculations, I calculated as though they would walk 8 or ten hours, eat quickly, rest 6 or 8 hours, travel, rinse and repeat. What do adventurers care if they are walking at night?
Rules-wise, though, the wizard, sorcerer, barbarian, and anyone else who has "per day" or slotted abilities is going to be outta luck in 3e. You're only permitted one rest-and-reset per day. If you started at sun-up, the earliest you can continue is tomorrow at sun-up.
I have no problem with a raid on an overlord's castle taking two to three hours, in game. It isn't literally the "15 minute day" that bugs me. It's the anti-cinematic feel that comes from fighting a couple of guardrooms then having (and being allowed) to rest. If you can't handle the guards and keep going, then bring an army. If you don't want to set off an alarm, just how infrequently do you think the guards check in, anyway?
I can see the excitement in having to hold up in some nook in the Temple of Elemental Evil. It shouldn't be after every room or two, though. It shouldn't even be after every four rooms, usually. Your group should be able to make a significant impact before you rest. There should be a reason why they don't just mass and squish you.
Cave complexes can work well for this because you're essentially doing underground wilderness exploration. "And, today, we found the orc outpost. We killed most of them and the rest fled. We should have just enough time before they bring reinforcements -- if they intend to reclaim this area -- to tend the wounded, eat a meal, and get some light sleep."
But a lot of settings really don't work as well. I mean, really, who in their right freaking mind -- or even as nuts as adventurers -- is going to camp in Castle Ravenloft?