Day/night... you know you guys are itching for it!!!
Also, there should be some kind of 'improved torch' that could last for a longer span of time, than the normal one...
Also, making it so some enimies (ie bomy ghosts and zombies) come out at night or so... or perhaps the haunted houses materialize at night, and disapear at day....
could also make it so the boss monsters come out at night more than at day.
Could also make room for some fun quests like vampire hunting, and lyncanthrops, etc.
Maby make it so the farther you stray from a path/city, the darker it gets, and wolves are closer the the entrances to dungeons?
Maby make some jobs you could hire for to make some easy cash if you're a newbie (though this is an entirely different sugestion, it still applies to the thread... just keep reading and see...)... such as being a torch carrier and help npc people get between towns at night
Maby make lunar cycles, so when there is a full moon, it is rather illuminated... and when htere isn't a moon, thieving might get a bonus, etc, because it is so dark.
Maby make it so mp regains faster when there is a full moon, etc.