Had Europeans not colonized China, maybe we wouldn't have that little communist northeast China next to Korea and the Republic of China in the south. Our colonization kept them fragmented which helped Mao gain a foothold in the northeast. Tragic.
I could see the Gansu-Shaanxi-Shanxi-Hebei border be a simple provincial border rather than the border between two nations claiming the others territory. I read about a North China citizen getting shot trying to defect crossing the border in November.
The UK might've been encouraged to give up Hong Kong to a unified China, if they also hadn't around 12% of the HK population there. And Tibet might not have gotten it's independence and India might not have lent aid (for a favorable border settlement) in the China War back in 1948-1952. Who knows, maybe Korea would have fallen to the commies back then or even be split in two!
I'm pretty sure the western Europeans wouldn't have kept their concession territories in Shanghai, Shameen, Hainan, and so on. Chang Kai Shek did a lot of dealing to shore up his power, but in the end he still got toppled. Though, I guess that's a good thing, for South China at least. They've opened up a lot more and liberalized their economy a lot. The dichotomy with the north is staggering. They keep saber rattling to get foreign aid from the UN to prop their regime up, while South China has had practically 5-8% growth year over year.
The only things really holding them back are the German Naval base in their Kiautschou Bay, along with Japan, Korea, and the Dutch Navy in Formosa. The US having bases in Japan also helps, along with the UK in Hong Kong.