Pants! 说:
Oh great, you know what you're talking about! The discussion got that much more interesting!
On the historical note, I read several times that mongols despised the chinese, that a steppe pony was far more valuable than a peasant. For that reason chinese prisioners, and by that I mean levy soldiers and general armed peasantry, were used during sieges to push catapults, siege towers, fill moats, place ladders on walls, and all the work that needed cannon fodder during the first mongol invasion of China, while Genghis ruled. Granted that they salvaged blacksmiths, engineers, artists, and all the cultural and technological elite of the conquered lands, but I dunno if they actually employed former soldiers into the Imperial Army.
Now I really do not know how was the army composition of the Empire under Ogedei, if they used Chinese auxiliaries as they kept pushing into China and Korea, but I always had the impression that the Golden Horde, which I believe to be the inspiration to the Khergits, was an all-cavalry force that kept hitting and running for kilometers, luring the cocky russian nobility into recurrent traps. If I am wrong, I would ask you to enlighten me on the matter
Now about the sieges, in NE the Khergits have little to no problem in sieges, thanks to those little dudes called Lesser Khans. That crazy golden armor of theirs, their khergit bows that give piercing damage and with a katana, they usually cut through everything. The fight gets interesting when they clash against paladins and blademasters, where they have a slight disadvantage. Not to mention the rare-but-unstoppable Boyons, the end-tier unit of the lancer troop tree. I think that giving them even HEAVIER infantry is an idea to be looked into.
Anyway, it would be actually fun to see some dudes wearing that samurai-like armor that is hidden within the game, it reminds me of the chinese armor that the mongols copied, and that M&B's CG artist Badamkhand drawed so flawlessly on the loading screens.
Finally, after reading your arguments I realized that I'm not fully against the Khergits having infantry, but I am against Khergit infantry. A Khergit cavalry core, with their stunning golden(and perhaps chinese) armor marching behind an army of blonde lamellar-armored, axe-wielding slav auxiliares seems appropriate. I am against, however, of the Noyan/Orlok infantry type, i.e. khergits on foot. That is utterly wrong, given their steppeish culture.