Oh boy I'm excited, since it seems like the editor is in line with my expectations. I was a little disappointed by the editor tools for the first game. While they were fairly powerful, they were not at all intuitive. Given the lack of mods from other users, it would seem many shared these feelings.
I played around the GM mode for a while and found that even the in-game GM mode gave the player a lot of options for managing the campaign, which is excellent. Terrain editing and something like conversation/goal scripting are things for the external tools, and I'm hoping (and I guess expecting) that these are things you can do within the editor. One thing I found nice about the GM mode is how easy it was to use. The interface worked pretty much as expected and I didn't really find myself getting stumped with anything. Given how the GM tools exceeded my expectations, I'm really excited about the editor tools.
Mainly, I'm just interested in what other users can create. I don't expect some 60 hour AAA RPG quality, nor the huge persistent worlds of NWN, but if I can get an hour long dungeon crawl with traps, puzzles, and some sweet loot, I'll be more than happy.
