They don't want to make it outside of American because reasons. I don't think their current team has the skillset to justify that idea. If it was Tim Cain I would believe he had a good reason. But current fallout writers aren't on par, so why not make it more interesting.
It would have to be more melee based, maybe in a northern area of Europe with a heavy scandanavian focus.
Maybe the radiation gave them magical abilities. Have a sorry redneck excuse for a magical college up in the north east of the map in the remnants of a ruined city.
No bad, Fallout shouldnt have fucken magic. Its pulp Sci-fi sure but at most it should have NPC psychers nothing more. We dont need to fucken have special magic abilities in everything.