The Neverwinter Nights (NWN) game engine represents what I hope to be a new era in computer gaming: platforms that invite users/players to create their own games with near-complete access to the game engine.
Sadly, while the NWN platform itself was a major breakthrough, the included gameplay was routine, uninspired, and sometimes even silly. Shadows of Undrentide (SoA) shows that the Bioware crew can not only create a great technical product, but also deliver a solid story.
Unlike the original NWN storyline, SoA has a coherent plot that, while short of "compelling," kept me interested. The fact that it was written for single-player mode meant the storytellers could focus on developing non-player characters rather than try to have the story work with lots of different players (not an easy task!). While many have complained about the lack of multi-player support, personally I've been unable to commit to that kind of gameplay anyway, and the few experience I've had were disappointing.
The fact that NWN is both a generalized toolset and a game means a lot of tradeoffs: one is that the graphics and environments become pretty uninspiring after a while because they re-use the same assets over and over again. To me, this is almost a blessing, as it forces story developers to focus more on the story rather than dazzle players with graphics.
Toolset enhancements and expanded assets (monsters, spells, etc.) make this expansion essential for those of us creating content.
Although not approaching the peaks of the Infinity Engine series of games, the NWN platform still has a lot of room for growth, whatever the power-gamers who want shiny graphics instead of good stories might say.