If you include Rhun as part of Mordor. Rhun was always fertile grasslands surrounding the Sea of Rhun. What people consider Mordor is usually the furthest western areas around Mount Doom and Barad-dur. That was inhospitable, but Sauron ruled over the men who lived further east for centuries, and their land was always fine.
I like the Théoden and Balgruuf comparison, but I think the Legolas-Faendal is true to the extent they're elves who use bows.
Witch-King and Dagoth Ur is pretty nice too, but Dagoth Ur wasn't really the servant to a greater power.
Which makes me think of comparing Mannimarco to Sauron.
Powerful magic-users who served entirely evil masters in the past, but their masters were destroyed. Both associated with necromancy, and both portrayed themselves to their followers as gods, and both defeated but not entirely destroyed.