I'm thinking of creating a bug report with this title. Thoughts?

My experience with roguelikes is limited to 4 or 5 games. Only one had the ability to sleep, and even that one didn't actually keep track of sleep deprivation, it was just a means to explain what happened when the character chose to wait for several hours at a time. (ADOM equivalent of w5'ing for many turns.)

In ADOM now, the character never sleeps, for months, and there is not only no explanation or magical rationalization, but also not even one word of mention.

Adding sleep to the game would require a lot of programming (I think) and a whole lot of adaptation from players. Cost / benefit ratio might be too high.

I envision a sleep counter along the lines of satiation value. Different races, and perhaps different classes, would get sleepy at different rates. (Perhaps certain skills would also affect sleep somehow.) A state would be added to the summary lines at the bottom, again similar to satiation, perhaps something along the lines of "Exhausted / Sleepy / Tired / (null) / Jittery".

Nodding off when a hostile is in line of sight would be virtually impossible for any hero, due to every humanoid's biology including some sort of adrenaline equivalent. However, there would be penalties (again, similar to satiation) to DV and Perception when Tired or worse.

Camping in the wilderness might be relatively safe. For long dungeon crawls, people without magical means of staying awake might choose to use wands of door creation and lock themselves into a room to sleep for 8 hours.

Etc, etc. It's a whole can of worms. Fun! Or ...?