Tbh if it was on a new map that's larger and denser than anything we have, they could turn pvp on inside of it too and make it a lawless wasteland akin to Mad Max. Make enhancement cores, cranked up legendary drop rates, and cranked up XP the reason to brave the place. Add in some world bosses that are hard af to kill for adept versions of various world drop weapons. I wouldn't propose adding in higher exotic drop rates or prisms and shards, because nightfalls need to stay relevant, but I think an optional zone like this would be super fun.