Reason
Playing with an evil faction (especially orc factions) is always harder than being good. Their biomes tend to be poor in resources, food is scarce, and I think we've got to address the fact that the orc factions (mainly Mordor, Angmar and Dol Guldur) should have more structures. All three mainly have towers and tents, while it would be great if we made them more unique, with more complex, custom and lootable structures. I don't mean we should create Orc villages or taverns, but militaristic or economic buildings would make exploring Mordor or Dol Guldur vastly more entertaining, in my opinion.
Proposals
A very important faction in Middle-Earth, that is yet so undeveloped, is Mordor. Representing the pinacle of evil, I think Mordor's barren landscape should have more than just a few tents and towers. In addition to this, with the introduction of sub-factions, comes the potential of creating unique and custom structures to Mordor. Gondor, for example, has many different variants of fortresses and other military buildings. Why not have a large prison on the plains of Gorgoroth? Mines and watchtowers in the mountains? Large warehouses in Nùrn? Trading posts in the Eastern Desolation, for Rhunic merchants? An Orc draught brewery in the Morgul Vale?
I aslo think that Mordor, Dol Guldur and Angmar should all receive a walled fortress each, which could vary depending on the faction (Dol Guldur's could be more sorcery-oriented, for example, with enchantments and magical brews).
Conclusion
I just think all of these elements and structures, which could provide loot and exploration as well as quest oppurtunities, are essential to making Mordor and other Orc biomes more entertaining to explore.
Thanks for reading, and please consider these proposals!