NWN2: Mask of the Betrayer - Interview @ FiringSquad

Obsidian's Kevin Saunders has been interviewed about Mask of the Betrayer at FiringSquad.  Here's an intriguing hint about a new gameplay system that has yet to be revealed:

FiringSquad: What other new features will the expansion pack have?

Kevin Saunders: There's one major gameplay system that we've developed with Wizards of the Coast. It's not something from D&D, but it's D&D flavored. This new feature has both combat and conversation implications and is intimately tied into the story and characters. We'll be releasing more information in the near future.

We implemented many other new features, most of which are to further polish the NWN2 experience for both the player and for the content creator using the toolset. For example, we added the ability to use any 2D graphic as a custom portrait for creatures instead of the automatically generated 3D portraits.

And, of course, we added a lot on the gameplay side, including over 50 new spells, over 50 new feats, new items, crafting system enhancements, etc.