I've been thinking this myself, because I just did open up the Course Maker recently, and generated a few tracks that have really floored me with an amazing racing experience. One in particular has become my favorite, a long curvy mess I named Excalibur, something like Virginia International Raceway with the road features of the Nordshleife. There are a few that others have made that I want to download, and they would be nice additions in GT6. I'm very hopeful that they will port directly into GT6 with perhaps some trackside improvements.