RPGDot has conducted an interview with Obsidian Entertainment's Chris Avellone, quizzing the designer about their upcoming Neverwinter Nights sequel and his experience writing for previous RPGs. Here's a taste:
Q: You said in a previous interview with The Star that you believe the story should come first and game design should follow. How has this happened with NWN 2?
A: I don't think story is more important than game mechanics, but I do feel you can get some really interesting game mechanics if you let the story push the game systems rather than tack on the story to some game mechanics.
If your story has dictated that all a character can do is bite opponents (Morte, Planescape: Torment), then solving his inventory weapon upgrade problem suddenly becomes a lot more interesting... and can lead to things like living teeth that he can find and bore into his jawbone to become fangs, and crazy stuff like that. However, sometimes those story-driven elements can cause a lot of development headaches - for example, Bao-Dur from Star Wars: Knights of the Old Republic II: The Sith Lords lost his arm in the past, so the amount of model and armor variations we needed to make his force field arm work was a little nuts, and made Ferg grumpy.
Anyway, as far as Neverwinter Nights 2 goes, Ferret Baudoin (our lead designer) started with a pretty good technique - he laid out how he wanted the player to feel while playing the game, and then he structured the events and game mechanics around it to reinforce that feeling. From there, he made a story backbone, fleshed out all the major enemies and companions, the events in the Acts, and then it was divided amongst the designers. I can't say too much on how the story premise affects the game mechanics without giving too much away, but I will say I like the direction and think it's a strong one.
I will say that we also tried to make sure the creature allocation and terrain allocation in Neverwinter Nights 2 was set up in such a way that it not only helped the story, but the monsters and terrains we included for the story were ones that would be the most valuable for the module-building community as well. We recognize that our resources are not just for us and our story, but for the end-users' modules as well.