Well, say you did have Fallout 4 in China.
Do you guys remember that when the US counter-invaded China, they captured several cities, I think Hong-Kong being one of them. I believe the US held onto those cities unto the great war also.
You could center the game around Hong Kong. You are a descendant from a group of survivors that had its origins in the American Military, but who went AWOL once the bombs started to fall and took shelter outside of the city in a old underground US Marines bunker. To this day the colony still survives (whatever year it would be), however something happens inside of the colony that they need to send someone out to search for something (I know this has been used so many times). Lets just say the generator is slowly going out, and without the proper parts to repair it, the whole bunker and colony will be without power (which they rely on for everything, including the growing of their crops, and the running of their water purification center).
So before they send you off, they give you a PipBoy (that was brought over from an American trooper who was part of the group of US Soldiers to defect), a 10mm pistol, a few Stimpaks, and send you off. So they send you off to look for a working engine, however this generator is one of a kind, for it has enough power to power an small city. They give you their only lead, an old Power Plant in Hong Kong. You comb your way through the ruins, picking up better equipment as you go along.
You finally get to the Power Plant (you should have moderate equipment right now, such as some shoddy armor and a mediocre weapon), and find a small community living there. There they lead you peacefully to the generator, only to find out that it is broken, and has been that way for decades.
However after spending time with the community you just met, you find an old man, an old scavenger who knows his way around Hong Kong and the outside area. He tells you he knows of a place that may have this generator, a working one also. However, they need help, they need YOUR help. There is a group of Chinese raiders threatening them. They are running low on ammunition, and people who are able-bodied to defend their community. They ask you to wipe out the raiders, before the raiders wipe them out. Here you now have three options:
+ Pass a speech check, and the old man will tell you anyways. However the next time you come back to the Power Plant, everyone will be dead, along with some (very few) raider corpses.
+ Kill the raiders, or pass a speech check, and convince the raider to let you see their leader. Kill their leader outright and escape, or pass another speech check and convince the raider leader to stop attacking the community at the Power Plant.
+ Or search around the Power Plant, pick a lock, and eventually come to a room with an old Chinese computer still working. You come across the information you need in the terminal. If you leave and come back after going through this option, when you come back the Power Plant will be under attack by Raiders, and this will happen at a 33% chance every time you come back to the Power Plant until the community at the Power Plant is wiped out or you do the Raider mission.
Lets just say you went about it through killing the Raiders, you go back to the Old Man and he tells you that there is an old Chinese Military Base to the north, outside of Hong Kong, with running electricity in every building. However he states that it is guarded by the "Reds", a nickname for a group of Chinese nationalists trying to take over the area and restore Post-War China to its former Communist glory at any cost, including slaughtering entire towns and communities who stand against their will.
(Obviously these guys are the antagonists).
This is the end of my "introduction" to what one could be like. I am telling you guys, there could be a way to make this game work, and it could be cool as hell. Then imagine if the original Fallout team got together to do it?