Ok, I think there’s enough interest for me to start putting this together.
For nether I’m thinking about making it either infinite like it is now, except all portals must go back to the overworld area that everyone is stuck in, or limiting the nether region as well. Maybe fudge it so there are netherbricks and netherwart accessible, but not very much of it. I feel like the nether should still be there though.
As for spawning in the world, everyone will spawn at the same location when the event begins, then respawn whenever the map resumes exactly where they were when it ends, so there won’t be a “spawn” so to speak. If someone manages to find where you respawn to and they take it out, then I think yes, you will respawn in a random location. That, or give someone a minute of immunity (but essentially make them a peon) so they can escape whatever is going on at a central spawn point. It might not be in the best interest of people to grief that point, cuz they will be victims of it when they inevitably die as well.