Fallout's world definitely has lots of potential for different stories of survival ongoing at the same time, unaware of each other.
Sort of a grand rebuilding-from-the-rubble theme across various parts of the world, if they manage to pull it off that way.
more wonderful still if they can make the outcomes from all of those culminate in one finale.
i.e. DC develops water purification, some other area figures out a cure for mutations, and so on, and eventually the world is on the way to getting healed. That would be more epic than any other fantasy setting, IMO, because you would be able to appreciate all the minute struggles which make that possible.
What do you think?