Damn it, wrote a long post and the stupid Internet ate it!
About a year ago, when the idea of expansion packs first started being mentioned on the NWN forums, David Gaider asked everyone what they most wanted to see. After long discussions, he mentioned that the first expansion pack wouldn't feature much in the way of engine improvements, or toolset improvements, but would be more of a "add some content" expansion. The second one, however, since it would have a bigger team working on it, would accomodate many of the requests, or at least try to.
Most notably, people wanted the ability to attach scripts to items (the lack of which is the fucking DUMBEST design decision Bioware EVER made), far better henchman interaction, being able to carry local variables between modules and tons of other stuff which are currently making module makers' lifes miserable.
Now, granted, this preview by Gamespy doesn't necessarily tell us everything there is to be in the expansion, but all I see is more classes, more spells, more feats and a "make your own potions" system. (Hello, open five chests and you'll have 1800 potions, does anybody really NEED to make any potions with the way the treasure scripts hand them out??)
In short, it just looks like "more loot" to me. A few more monsters, great, especially since quite a few of them have already been made and released by the community well over a year ago (beholders), the drider is exactly the same as those ant people you saw in the first expansion, and why is Gamespy getting excited about Drow, exactly? They're already in the game.
I think Bioware designed the engine to do something totally different than what people were wanting to do with it. Most people want to play with a large group of players in a persistent world, preferably run by multiple DMs. The NWN engine was made to create and play simple single player adventures. And despite their (well intended I'm sure)promises to add this kind of functionality, I think Bioware is just finding it impossible to add to Aurora.
I hope they'll forego making more expansion packs, and start working on NWN 2, which will hopefully deliver everything that most people were expecting from the original.
One thing that does look promising though, is the removal of the experience cap. Bioware did this before, in the excellent Throne of Bhaal expansion for Baldur's Gate 2, and it still ranks as one of the best expansions ever made in my book. So that looks very interesting.