No comments as to balance, but just a question as to whether you're intentionally changing spelling vs. the LoTR text? (for instance "Mordar" vs. "Mordor" and "Eleophants" vs. "Oliphaunts" or "Mûmakil"?) I'll assume that your unit descriptions are mostly placeholders for now; some of them are incorrectly assigned (e.g. Sorceror shares the same description as the Balrog.)
Also, I see that you've included a "Wraith Lord" unit. Note that there is already a "Wraith Lord" unit in the game, and if you keep the same unit name you'll overwrite the description for the out of the box unit type. The same thing applies to "Sorceror" and "Wolf Rider".
Finally, you may be interested in the Kingdom of Angmar mod, which is also based on Tolkien.
http://forum.shrapnelgames.com/showthread.php?t=44148