I'm a GSP fan and I think this matchup is interesting stylistically. I also believe that this is the one fight that made GSP even consider making a comeback to the sport. He saw another opportunity in Bisping, took it, and was successful. But this fight is the one he really was looking for.
Now, the two biggest UFC PPV draws clashing would be huge, and is exactly the kind of fight that the UFC is promoting as of late (money fights) and in which both fighters appear to be interested. Why the hell not?