I think the Late Sheldon Brown had a tremendous history on all Bridgestone including catalog scans. The Grant Petersen cult is real. Some old BOB members went over to Rivendell right after Bridgestone North America folded in 1994. But you’re right, the 1993 model changed over from the 1992 model. Specifically, caliper brakes to cantilevers. But I think the reason why the XO-1 is still a desirable bike has a lot to do with Grant’s vision of what an all-rounder/rando/off road touring bike should be. Doesn’t mean it’s perfect, but it inspired many bicycles and frame builders around the world. So, that’s saying something.
I own a 93 XO-1 frame and fork, which I’m selling, actually. Personally, I think they’re made to be enjoyed instead of collecting dust.