"There was no Day/Night cycle in TOB, just a scripted version of Saradush at night where a specific plot event occurred."
I am not sure what constitutes a "scripted event", but I just opened up the Throne of Bhaal game (PC version) and played ... I entered Saradush at clock Day 0, Hour 17. Then if I just stand there and do nothing, the clock continues to advance and it eventually becomes night. No trigger event needed, the clock just runs and the sun goes down. The Watcher's Keep has a running clock. The Oasis has a clock, and you can rest there and day/night will cycle with different light levels accordingly. I know this because I just did it with an old save. Same with the North Forest and the Forest of Mir areas ... all of them have normal day/night cycles and you can rest through them. I don't know, maybe there is a difference with console versions of the game, but day/night is definitely a feature in the PC version of ToB, and it's not just in Saradush, either.