The beauty of it is the pointers. Figure out the algorithm and it'll be no problem at all. It'll take time to do but anything can be cracked with enough time
The more people working on it the faster it's cracked.
The website GR2Decode or something like that is someone I'm going to reach out to and anyone else that has been working on GR2 files. See if I can't stir up some enthusiasm. The QuArK people are another good one to reach out to.