Wot m8? How is it a failure to not attack the Timurids first??????????????
We could discuss without using internet slang, couldn't we?
Now, I could always go for "Rolf U not see te . d00d" but it's going to be quickly tiring for both of us.
It wouldn't be objective failure of course : I was talking about people that lost ambitions, high positions in the court with Yongle's coup.
These could have argued that Yongle made a grave mistake by not attacking Timur when he was still outside China, as he did IOTL against Mongols, instead of waiting for Timur to attack the Empire.
Basically, accusing him to have mishandled this : after all his envoys were either made prisoner or outright killed.
Again, not that it would have been objectively been a good thing to attack Timur, but it could have been argued against him with more or less success regardless.
The Timurids didn't deal with it on such a large scale, though.
I beg to differ : Timurid first campaigns were made into the Central Asia, whom desertic and semi-arid conditions aren't radically different from what you encountered in Xinjiang or Gansu.
The disadvantage is real, but not an unbreakable obstacle (or Timur may simply not have attempted : it's not like we're talking of a wannabe khan, but about someone that showed off military skills)
Besides, don't forget that there's Tianshan, Kunlunshan, Qilan, Taihang, and Qinling, ALL in his way to China proper.
I'm going to repeat myself, but I don't think he would even have attempted to conquer all of China, but to slash the Ming pretension of vassalage of Central Asia.
If obviously successful in this region, he might have attempted to go further, but that's more of a secondary objective : the goal is more geopolitical than full fledged conquest of China.