Hear me out on this one. No new planets have been announced to be unvaulted next year. They could just leave it a floating destination, but that would be a bit weird, all previous raids being tied to a destination. So it will be tied to a destination, but where? For this we look at Crucible maps. We actually have quite a few D1 Crucible maps in D2, they just have had a reskin. The map the Forgotten Shore (I believe that's the name), used to have a much greener look to it, because was located on Venus. It is now on Nessus. With Io gone, Nessus is the only planet with a large Vex presence. Also, it is the only planet not vaulted (besides the EDZ) that does not tie in with the Forsaken story, the Shadowkeep story, or the Beyond Light story. Besides a few strikes, there is nothing to do on Nessus. Placing the Vault of Glass on Nessus wouldn't be to hard to justify either. Vex like to bend the rules of time and space a lot. Creating things that exist in two places at once is easy for them to do. Having it on Nessus would also make it new enough to keep it interesting for D1 players while still keeping it a nostalgic raid experience. For all these reasons, I believe the Vault of Glass will be returning on Nessus.