Researching medieval history, an interesting point I've thought about is what if the sultan of Khwarezmia hadn't been a total idiot and massacred Temujin's caravan and ambassadors, which directly led to war between them and the Mongols. Khwarezmia was one of the most prosperous empires in the world, with a city of Samarkland holding well over a million people inside, along with libraries and centre's of culture of profound importance to the Islamic world, second only to Baghdad. Even an entire ethnic group which had now disappeared in favour of Persians and other Turkic peoples. There's no doubt Khwarezmia would have fallen eventually, but probably not in such a devastating fashion. I wonder if Central Asia would have done a lot better without the yoke of the Mongols and becoming a backwater for Russia, China and Britain to compete over.
On the contrary, how would it have affected the Mongols? The conflict forced Genghis to fight a war on two fronts (three once the Xia Xia betrayed them) as opposed to a united front against the Jin. Genghis diverted probably 100-150k men to invade Khwarezmia and a not much smaller one to invade Xia Xia, who had bent the knee before hand but used the second front as an opportunity to betray Genghis (really didn't work out well). I don't think the Xia would have dared to betray without a second front, and so assuming no one backstabs, Temujin should be able to focus all his resources on the Jin. Meanwhile, Khwarezmia continued on its quest to build up against the declining Abbasids.
What do people think of this analysis?