Why are cavalry units so slow and weak?

[fallen851]

I only barely won 1v1 with royal kinsmen heavy cavalry against Arabian slingers, and that was only because they had less valor and routed kinda easily. I was losing most of the battle. In regular RTW, it would have been an instant victory for me.

I currently hire nothing but Caucasian archers plus a few spearmen. Caucasian archers in this game are amazingly powerful for the price. I've got some royal kinsmen heavy cavalry just because my family members keep having children that come with free cavalry units.

I really find that hard to believe that your family members bodyguards almost lost a melee fight to Arabian slingers.