Dark Dreams of Furiae - a new module for NWN:EE! Buy now
For replay ability, have the placement of traps and non-plot loot be random. Right now I know exactly where every trap is in the saga. But if a hallway is trapped in one play through and a door in the next....or if this time it hits me with a fireball and next time a lightning bolt, then the replayability will be much higher.