Warband intentionally has ok graphics, at max they actually look really good. Even a high end video card will have trouble with 200+ players/npc's on a screen with graphics like war of the roses or chivalry. My friend's gtx 770 ($400, very good graphics card, can run crysis 2 at around 60 fps on ultra) sometimes reaches 30 fps with 300 npc's on screen in singleplayer! So imagine that with chivalry graphics probably wouldn't be so good.
So I think they will improve a little bit but not too much where you are gonna be able to compare them to chivalry or something like that.