Dont know if this has been brought up before,and I am sure it has, but I believe it will bring a fresh perspective to all quests in the game. Instead of having all the monsters in static locations so parties can prepare for them and cast spells on a known location, make them wandering or in random locations throughout the dungeon. This will keep parties on their toes a bit more and keep quests from becoming stale as it will be different as far as a monster location every time. Heck, you can even toss in a new monster in a location or two and the reason can be that monster wandered in to the dungeon form another location. Imagine this scenario, we will use an old staple quest for it, WaterWorks...
Your running in WW and you come upon the bridge with the kobolds in the middle of it on your way to get the first part of the quest, except this time the kobolds are not there. You run to the middle of the bridge to be greated by 2-3 minotaurs that went down there and scared the kobolds away. You take down the minotaurs and walk a little further and the kobolds with the wovles are no longer there either, so you walk a little further and are ambushed by the kobolds that were supposed to be at the middle of the bridge back a little further.
I dont know how hard this would be to code, but just putting monsters in different locations every time and having wandering/random monsters would breathe more life into all the quests.