Okay, i know this has been discussed a million times before here and there, and most ppl say Fallout will never set outside United States.
Myself will also be pissed off to see a major sequel to be set in China, bt it doesn't have to be a sequel, it can be something like how New Vegas is distanced away from Fallout 3 in the sense of geographical location, it would be cool, no?
U may say most Fallout players are Americans/Westerners who are not interested in playing in a foreign country, bt wt can be more fun than playing an American remnant in post-apocalyptic China? as Shi of San Francisco, plus, China isn't just a random 'foreign' country, it is the primary rival of U.S. and half the reason of why entire world has gone hell!
as an American remnant in China, you can fight you way up, dealing with various Chinese factions that some have already forgotten/forgiven the old world and are friendly with you, while others are still hostile, or maybe you can also discovering the original cause of Great War and see through events from China's lenses, or even try to stop certain faction from launching another nuclear rain upon NCR and BoS in American mainland, making a difficult moral decision between either siding with post-apocalyptic Chinese (who are your lifelong friends), or saving mainland America (where is only connected with you by distant past, a place you have never been to and never will)
Anyway, im not Bethesda's lead designer of Fallout series, nobody listens to me :(