Ghengis really lived in the 12th century, and although his keshiks were feared for their use of bows like horse archers, they went up against chinese pikemen and crossbows and won a lot of battles. Historically they seem more like knights to me, they fought around that time period and against medieval style opponents. Also I have read of ghengis adopting the use of long spears like lances, very much like a medieval knight. I think it would be more accurate and cooler if keshiks were a knight replacement with 10 str and a first strike chance and ignoring terrain movement costs, basically their upgrades from horse archers but on knights instead.