Mongol's UA is great, works well with the new changes to CS bullying. I have some ideas for the Khans though. the first 2-3 Khans are really useful to help resupply the army, etc. but especially with their speed you don't need too many great generals to help with the army, and they just create normal citadels, which I don't find that useful to Mongolia anyway. I was thinking it could be interesting to create a special GP improvement, much like the MoV gets with the Colonia. It could be called the Ortoo, based on the vast supply route network built by Ghengis Khan across the Mongol empire.
I was thinking you could remove the land grab part of the citadel and replace it with either a reverse feitoria effect (adding gold to internal trade routes to the nearest city to represent silk road merchants using the checkpoints), or an effect like hospitals in cities where the unit stationed there heals regardless of whether it made a move, allowing for a quick heal if one of your skirmishers gets hit. The reverse feitoria effect really helps for mongolia considering that if you're eating city states and warring with other civs, you probably won't be able to keep many international trade routes going
