The problem is that dungeons are 100% randomly selected and that ALL of them are eligible for selection barring the very major locations. The game doesn't take into consideration where you have been before or what you've cleared. I've had a few instances where I've been sent to the same location twice in a row or to places that havn't even respawned yet. On one occasion my Companions quest line became broken due to this.
The biggest issue with radiant questing is that it easily breaks other quests because it can send you anywhere. Some of the hand crafted quests have fixed locations, etc. If a radiant quest sends you to one of these places the odds are you're going to break the quest or event that is supposed to take place there.
As I said I like the radiant quest system but its tendancy to break other quests really puts me off doing it. I've gotten to the point now where I save before enquiring about quests and if it gives me a radiant one I reload and avoid it.
An example of what I'm talking about..
Radiant quest sends you to collect an item in Mystery Cave X. So you go there and clear the place out on the way to the chest in the end of the dungeon. Guarding that chest is Murderdeath Lord 2000. You take him out. Later on you get a hand crafted quest that requires you to go kill Murderdeath Lord 2000 so you go back.. to find a corpse and a broken quest.
