Well, if you refer to End of Empires in particular I can say firmly that we see a tiny fraction of the total area of the steppe, and there are interesting things brewing in the distance. Some of which will come into view very soon.
I will consider your NES officially redeemed when someone other than the Satar and their cheap knock-offs comes from the steppe to ravage the periphery of the civilised world.
Sure; if one category is a pastoral horse-warrior culture, then we could create a similarly broad (and similarly useless category) containing all sedentary despotisms.
See, that's confusing because I've seen professional historians use that as a genuine dichotomy, if a one that admittedly didn't quite apply to the many, many hybrid states - nomads going sedentary (Uighurs before the Qing wiped them out, but also others) and agrarians incorporating nomadic structures and systems (Muscovy, Manchuria). So obviously the ones that actually ended up being qualified as pure "agrarian despotisms" also usually coincided with what we generally consider hydraulic despotisms.
I suppose the agrarian despotisms really are potentially more varied, but that's why it's more of a shame that we don't see a lot of people properly dedicated to that mindset, as opposed to going on various distinctly non-despotic tangents. Not that there's anything wrong with that, but you'd think the classic version would be more prevalent than it currently is.
So going back to my original question, I still don't see enough of those as compared to steppe nomad empires.
ALSO: Someone should make a steppe nomad empire that is distinctly peaceful and mercantile. It'd be kind of like Reasonable Marines if you know what I'm talking about, not to mention not really clashing with what a lot of them actually wanted to have - after all, it has been well argued that Genghis Khan's nonsense about the lamentations of their women was only ever singled out in the Secret History because it was an anomalous view among the Mongols.
Pardon? Are you implying steppe nations have had the same effect on every NES they've been in? If so, I'd really, really beg to differ.
You have to admit that it has been strikingly similar. A great horde of steppe nomads, always very martial and often wearing masks rolls in from beyond the limits of the known world (usually the north for some reason), attacks everyone for little to no reason, destroys a few frontier civilizations, damages some others, makes a third group its vassals and tributaries, unites everyone against it, suffers defeat and collapses into infighting, then falls back, reunites and does it again. Maybe this doesn't happen always but it happens often enough to grate people.
Also, each and every one of my targets wasn't expecting to be attacked when or where they ultimately were.
Well
yes, because it was with hardly any in-character rhyme or reason from what I understand. I honestly have no idea how your nobles put up with you so long, or how you didn't end up eating all your horses and melting away like snow after going that far away from the steppe.
It like, well, like Mongols invading Europe, pretty much.
And you were the very definition of amorphous because of it, too.
Originally I was migrating westward, hoping to reach the other side of the continent. Ultimately however that wasn't viable for a variety of geographic reasons, not to mention I had no way of knowing if there was any civilization there. So, I continued to expand the size of the confederacy, warring with other neighboring tribes and amongst ourselves. Then I reunified the confederacy under one ruler in the turn they reappeared on the map.
You'd think there would be something more to surviving a total defeat and exile than that, like cultural and socio-economic adaptations aimed at preserving your ethnic identity and surviving the hardships of an utterly unknown land where your old way of life was, at any rate, challenging to practice while you get used to the new terrain. I also don't recall anyone in real history doing the "run away a great distance for several generations, then come back the way you left and somehow conquer everything despite being isolated from key resources of a steppe empire such as trade income for hundreds of years" trick, but I guess they just weren't imaginative enough.
I'd love to hear it. Also, I'd put the reason behind your success more to your huge army towards the later part of your rampage. 
