It's not just that. I suppose you could play with clans, though I don't know why you would, but even with them the fact that they get rapidly reinforcing monotype units and are basically unassailable leaves them way, way overpowered.
Just played the Uyghur start mentioned earlier, 20 years later and I own Arabia, most of that time being spent walking because starting in the northeast corner is SLOW. Did it in ironman, here's what it looks like.
The main reason they're overpowered is their troops - after conquering the Abbasids I decided to destroy Byzantium, here's what the decisive battle looked like. Not very good commanders, attacking over a river and an equal numbered force with troops I can easily replace that would take many years for Byzantium to get back.
Over vassal limit, full of wrong-culture wrong-religion feudal holdings, and your steppe counties are rebellious. Seems like there's just 1 problem with that situation: steppe rebellions should be much more dangerous and wreck you if you're ignoring the nomad system.
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