You're not paying attention to the historical context.
Mordor as a power or a nation did not exist at this time; Sauron's (who was known only as the Necromancer at this time) ONLY place of power was Dol Guldor. That's why I said that the Mordor faction should be TC'ed into DG. Thankfully, there isn't a whole lot of changes that need to be done, so it will feel very similar.
The goblin faction is a pitiful laugh. They were never really a nation, and probably the only time the entire Goblin race fought as a single entity was at the Battle of Five Armies. They did nothing of significance in this time period. Change them into something else.

On second thought, don't change them into Lindon. TC them into the Wainriders.
North:
Arnor, Lindon, and Dwarves vs Angmar
South:
Gondor and Lothlorien vs Umbar, the Wainriders, and Dol Guldor