"Total War: Rise of Mordor" is an epic overhaul project based on "The Lord of the Rings". The visuals of the mod are based on films however the background story and rosters are accurate to the books.
The uruks have been upgraded. Couple of things are still missing such as a standard leather sash around their waist, but more importantly their bodies needs to be completely remade, so that's next on the list.
For now you can enjoy the new quality and diversity of the Isengard's roster. The units will be able to mix up the assets, but some parts are class specific.
And before you start complaining about the lack of white hands, they are prepared and there will be multiple variants for each asset via the decal system.