The cavalry mace perk is not worth picking over a better horse than the default, there's no reason to give up a longer weapon for a short one as a cavalryman. The long spear perk is also a no-no for me, since I'd rather have a bow and arrows or a shield to protect myself from arrows and couching cavalry.
I'd suggest an improved armor perk in the stead of the cavalry mace.
They can swap mace with the shield perk aswell. Tbh atm khuzait just feels like a worse version of aserai. Making them more light cav focused would make them more unique. Fighting against light cav is more fun aswell than fighting heavy cav.