I agree with carter in that PW builders arent the same as SP mod builders. From my point of view as a scripter, when Im working on a PW module, I tend to make numerous custom systems that enhance the game play with interesting features that players can spend their time with, such as a crafting system or housing. These things give the players something to do besides going out to kill monsters or doing quests. When Im working on an SP module, the focus tends to be more on the story and moving the player along through it, rather then creating something to distract them from it. PWs are built to last far longer then an SP mod (for each person that is) so they need such systems to entertain the players. Thats just how I see it anyway.