Hmm, I'd go for:
-Imladris (+Grey Company/Dunedain, Breeland & Hobbits)
-Mordor (Orcs + Rhun + Umbar)
-Isengard (Orcs + Uruk-Hai + Dunland)
-Misty Mountains (Completely redesigned, Moria Goblins + Gundabad Orcs + some of the beasts we saw at the Hobbit series)
-Harad (Haradrim + Variags of Khand + Half Trolls of Far Harad which are removed from the Misty Mountains faction).
The main reasons for dividing the following are:
-Rohan is mainly a Cavalry faction with strategies and tactics very different from Gondor which is mostly infantry focused.
-Cultural distinctions are huge between the elves of Lorien, Mirkwood and Rivendell. Plus the necessity to include the Dunedain.
-Making the Evil factions more book-friendly and include more "The Hobbit" content. Haradrim are removed from Mordor and have their own faction, as the book states that they're mainly a Cavalry army (different strategy). Mordor has more units from Rhun and Umbar though (Wainriders and Black Numenoreans). Also remove Mumaks from Mordor, because Mordor is a zerg-ish strategy faction relying on numerical superiority (again from the books). Mumaks are a little off that track I guess.
-Put some orc unit Isengard (as a very weak and basic infantry) and some elite Dunlending one - in books Isengard also used Orcs + Dunlendings were its strongest troops.
-Misty Mountains is completely redesigned. Most of its units didn't fit with neither books nor series. Moria Orcs are low-tier spammable. They are followed by Gundabad & Dol Guldur Orcs which are stronger. Beasts of War include: Cave Trolls, Gundabad War Trolls, Northern Wargs and Mirkwood Spiders(Desing like in the Hobbit). (I really don't know about dragons, but I'd suggest replace Drogoth the Dragon Lord with Smaug). I'd remove Half-Trolls, Spider Riders and Mountain Giants. Maybe those Troll Catapults as Siege Weapons.
-No Angmar faction. As much as I love it, it's completely wrong in terms of lore. Black Numenoreans are men from Umbar (not from the North), making up elite warriors / generals of Mordor's armies. In fact, I'd suggest to make the Black Numenorians as the Mordor's Hero unit (limited to 3), and the Black Uruks of Barad Dur replacing the "Black Orcs" as elite units.
Elite Dunlendings - look like elite Celtic warriors with large shields, chaimails and bronze helmets.
Haradrim - Un-upgraded have turbans and wicker armors. Upgrade replaces wicker armors with brass scales and adds brass helmets to the turban (book description).
Variags of Khand: Since Khand supplies Mordor with the best horses I imagined them as Arabs(of the Arabian Penisula) but maybe even a little like mongols - in contrast with the Haradrims which are mostly North African(I guess Variags wore masks). But Arab elements prevailing. The colors of their clothes
could be white and black (contrast with the haradrim red). Maybe even some Mughal inspiration.
Mordor Uruks: https://vignette.wikia.nocookie.net/eda ... 0823153326