As a mod author, I have one thing concerns me about Quake3 and Unreal Tournament: as multiplayer-only games, will they be lacking the hardcoded special effects that Quake2 and Unreal had included for levels and enemies in their single player missions? For example, in Gunslinger Quake I use a globe of darkness that was originally coded for an opponent included in one of the mission packs. How versatile and controllable will the lighting and particle effects be? In Quake2 they we predefined and hard to manipulate, but at least there were lots of them. I'm curious to see how things work out.