Mongol army needs more unit variety.

[matteus the inbred]

Fair enough, (and I have also complained to people about how limited Mongol troops are) but the fact is they never fielded anything like this at all, even if you allow them conscipted Chinese and Korean troops (which they only used in eastern theatres). Mongols only really fielded foot troops when they ran out of horses or used civilians to soak up arrow fire, and I don't know about allowing them naptha throwers either (although they did get quite inventive with explosives once they'd invaded China). I know army balance is important, but so is historical accuracy (to an extent, and this would be stretching it beyond what I think is reasonable for a historical game).
I think their command abilities and morale should be higher instead. They turn up with 2-3 star generals most times, which is rubbish. They won by tactics and ferocity, not technological achievement.

I agree totally with you that there aren't enough of them in the initial Horde, should be twice as many. One they arrive they can start fielding stuff from captured territories perhaps.

[Joshwa]

I always think the Horde should get loads of money when it arrives as well, and money every turn after that for a while. Come to think of it, rebels should as well, then they might actually build up some infrastructure!

[Knight Templar]

AFAIK, Mongol army who invaded Europe were only cavalry, so it would be nice Golden Horden has bigger variety of cavalry troops. They have only MHC and MHA, and Steppe cavalry which can be trained in steppe provinces.
I agree Golden Horde invades with too little (twice as more should be good) troops, I've never seen them (in game) holding Hungary and Silesia (like they historically did). Their units should also tire slower on the battlefield, and, like matteus said, their generals should have more command stars.

[matteus the inbred]

Ironically, I bothered to go and check some sources. As you say, KT, the initial invasion was entirely cavalry stuff, but later incarnations of the Golden Horde (from about 1251) actually used foot archers called Bessermeni (local Muslim town militias) and had Armenian archers, Siberian tribesmen, and even Italian mercenary crossbowmen called 'Fryazei' in their armies.
I suppose therefore that the most accurate compromise would be an initial Horde invasion of entirely cavalry (and siege weapons, I guess), then later they get reinforcements of mixed cavalry and foot...