I've decided that the version of China I described, torn by rival warlords, is too much of a cliche in recent fiction. Instead I'm going to have Japanese-dominated China (which was already the status quo in the 1930s) lasting into the mid-21st century, then the Chinese taking advantage of one of Japan's wars to stage a Buddhist-led rebellion. And yes, I am thinking a theocracy led by weird Tibetan martial artists etc. etc. As of 2115 China is mostly VERY peaceful, with the exception of a few areas where there are still the last remnants of the old Japanese empire refusing to surrender.