Fallout wont be taking place out side of the USA.
We are fast approaching the time when the amount of things we can do in the USA will be exhausted. We've been to Washington D.C. for chrissakes, the HEART of the United States. By the end of New Vegas, the entire USA is on its' way to some sense of returned order. How many games out there take place in post apocalyptic CHINA? In fact, how many games take place in China in general? Think of the fresh concepts and ideas brought on by the culture and setting. Imagine fighting amongst the rooftops of a dilapidated oriental ghetto in pouring rain, and imagine the different characters and philosophies inspired by Asian culture. Beyond that, it's an incredible bit of perspective, considering they were the aggressor in the War that caused the entire Fallout Universe. It's the mirror image of America. Imagine the war torn streets of shanghai, and there's this crazy military group that insists that the war with the USA is still going on, and they aim to resurface an immensely advanced nuclear strike submarine to assault Juno, Alaska, or San Francisco is you wish to be more cinematic. Imagine there's a rebel group forming that wishes for democracy rather than communism, and they begin looking for ways to stop the commie-Chinese before they re-destroy the world. And you a the player can choose which side you want to be on. Imagine the awesome locations offered by China, and imagine what they'd look like in Atomic ruin. Imagine an expansion where you journey into the mountains to defend a colony of Buddhists monks somehow immune to radiation, or imagine an expansion that leads you into the Gobi desert where you come toe-to-toe with a madman claiming to be the reincarnation of Kubla Kahn, and his vast army. Imagine an Expansion where you go to the city of Neo Tokyo, which is now completely flooded, due to a massive earthquake, in order to find a supposed Terraforming/weapon device created by a joint Japanese-American science program. Perhaps there's gangs of pirates in the Bering Straight, and you can move between an Alaskan map and Shanghai map by traversing the dangerous waters. Perhaps the game starts in Alaska, thus explaining what a possible caucasian/other minority is doing in China, 300 years after the great war. There are so many possibilities and fresh ideas never seen in an RPG before, to attempt in a China-based Fallout, that they'd be stupid
not to go for it.