Back in the '80s my best friend and I came up with almost exactly the same idea for a game. We called it "random" not procedural but with the idea that once a player discovered a world, it would be set so that every one else would see the same thing. The original algorithm would have some random components but would follow a set of rules. Back then we were coding in BASIC on a computer that took large floppy disks and would take hours just to create a basic star system. It was readily apparent that it would be some years before the game could actually be realized. Too bad we didn't stick with it. ;-( My fingers were crossed that Destiny would incorporate some of those world creation elements...