Nubian's in MTW were a favroite unit of mine. They were indeed jack of all trades so to speak and came out early. Im not sure why they arent so great anymore, but i defently think they should get improved apon.

And indeed i think there is actually ALOT of redundency in the unit selections for many factions. I have noticed that in auto calculateing battles, the AI gives the advantage to higher end units. So if you had an army of 5 dismounted fudal knights vrs 5 dismounted english knights, even though the fudal knights would win in the actual battle the AI (if you auto cal) will let the english win simply because there stats to the game seem "higher" even though they arent as good. And the men at arms thing doesnt make alot of sence to me either, but nor does some other units like some of the 2h'd ones, some cavalry units like the higher end ones being so expensive compared to fudual knights that do the same job and such (IE, kataphrats vrs lancers vrs lankton).