It's all about the things you can buy, On Druzzil most of the 65 crowd have worked out that the best Plate armour is in Nro so that attracts the majority of groups, the lower levels seem to prefer BB since it's the easist and the mid level bought items are better.
Rogues tend to try for Minaguls because of the 9% backstab mod on thier uber dagger for example. It's a compromise really and when you have unlocked a dungeon completely thier is no real reason to come back since you can use you points gained elsewhere anyway.
Edited, Sat Mar 6 13:29:28 2004 by tarv