we already have the infantry destroyers troop slayers player killers sea raiders, who are basically the ultimate enemy(except for high tier faction troops, but im guessing that sea raiders are more or less nord huscarls in bandit form) so how about the cavalry terror? the nords have good infantry so it only makes sense that their bandits have to be good too right?
well the khergits are almost entirely cavalry, so they have the same for bandits, but what about the high tier cavalry bandits? thats where horse raiders come in, they are more or less sea raider cavalry, because you need a reason to fear the bandits on horses too, they have cavalry bandits but they are more like normal enemies rather than enemies that will probably kill 2 troops per bandit,
now that i think about it there arent any master archer bandits either...
TL;DR sea raiders on horses in khergit lands because the current cavalry bandits dont strike nearly enough fear in your hearts