WI the Beiyang Government of China starting in 1912 was able to get a much, much firmer grasp on its own country, stifling all the warlordism and rival factions to get them in line? Perhaps having Yuan Shikai be less autocratic and ambitious would be enough, or if that's out of the question have him suffer an early death. Anyways, what I'm concerned with is having the Beiyang government stay in place without having the factions and cliques start warring with eachother and stuff. The KMT does not go off to create a seperate government, Duan Qirui is never exiled in the first place, Zhang Xun does not try to reinstate Puyi as emperor, etc. In short, the government itself does not become divisive and maintains much, much more stability.
Now, Yuan Shikai, before going nuts with ambition, was very concerned with creating a modern army based on the Japanese model. Let's say after his death his successors continue to do so. But here are where the questions start, considering there are no Anhui, Zhili, or any only real cliques, what happens to Sun Yat-sen? Does he remain in parliament and continue to be a major political figure? Do the Chinese still join the Allies, and are then any butterflies for WW1? Do they still get the short end of the stick from Versailles? And will the Japanese still try to invade China?