They actually made a pretty good effort to accommodate this with DOS2. I've seen some pretty stellar custom maps, and the DM mode is really good. However, I would wager that it sadly saw very little use. It has to be _very_ user friendly to achieve any sort of momentum, and it also needs to support persistent worlds IMO. Todays games just don't lend itself to user friendly module creation that well. Map design alone is something that was reasonably easy in NWN1, but jump ahead to NWN2 it became a lot harder. Modules were easier to make in NWN1 and the current online community is bigger for NWN1 than for NWN2 for just this reason. I'm pretty sure it would be much much harder to do in this engine.
My problem with DOS2's toolset is that you couldn't actually make single-player adventures, like in NWN or Shadowrun Returns. You could only make things that required a live DM playing in real time with a group of live players. You couldn't write dialogues and set quest triggers and such. So for my purposes, it was useless. I want to author adventures that people can just download and play on their own. (Or play cooperatively with their friends, whatever.)
