I vote no. I never had that kind of experience in Halo, which is the only other FPS I know of that really delivered solid custom functionality. Don't get me wrong, I loved the community creations in Halo 3 and Reach, but not enough to warrant gods-know-how-much time effort and money it would take for Bungie to make this something public accessible. I just don't see enough ROI for anything but a small group of hard core custom gamers