Having also spent a ton of time working with the NWN 1&2 tool sets, I found myself more than a little off put by the control scheme... Also its lack of activity feedback. I can tell that it was built for function and little else. But after a while I warmed up it.
Currently, my primary issue is the fact that ambient sounds don't stop when returning to editor mode, from game mode. They just loop indefinitely... If this is a bug, or if there is something I am missing, someone please point it out.
Lastly, what I am most looking forward to is the scripting. I have not looked very hard, but I see no attempts made to explaining it, nor dialogue. All tutorials and guides simply say both will be addressed/explained later.
