While in most games, hordes do tend to fall apart in the middle and later stages of the game, I find the power of the Golden Horde at the 1399 date way to overpowered. While Golden Horde seems to do great from that starting date, Timurids almost every time dissolve very fast. While I think it should be the other way around. While I think changes to the hordes awesome, I believe GH should be balanced out.
Just few years back, horde was utterly defeated by Tamerlane, capital and trading centers sacked and destroyed, large parts of it's army annihilated.
Even worse, Tokhtamysh (or Toqtamish) starts the game as a Golden Horde's general, and a very good one at that, while he should be a pretender backed by Lithuania nad Poland. While the alliance did suffer a defeat at 1399 at the hands of Khan Temur Qutlugh. The point is, Golden Horde's power was on the wane, and while Tokhtamysh's rule was able to spark a brief period of rise, it was already on a steady decline. So far I have never seen AI being able to fend them of (while on the contrast human player can do it every time) but as said, if I play in Ireland, almost every time I see horde strech from Novgorod and Krakow to Constantinople, Archangelsk and into Siberia. Ever worse succession crisis are never really serious as it should be. While Russian states were more or less tributes of the various forms of Horde untill 1480, in game they got eaten up very fast.
Every time I play with NON eastern European nation I tend to put Golden Horde's stability and war exhaustion at -3 / 15. I avoid doing it only when I play with Russians, since than it would be cheating. But the AI can't seem to handle the hordes, and more over, almost non of the states (Lithuania, Poland, Hungary, Muscowy) can't seem to institute Liberum Veto to fight them of at the early stage. More often than not it's Bohemia and Emperor who is only able to stop them.
Any ideas how to help AI fight them of without cheating ?