Hi i have some suggestions to the mod, they are my opinion so lets start.
1. This one is a little strange but here we go, there is an early, mid and late game, how about if we add something more, after reaching the late game in the citadel you can make an expensive upgrade to upgrade it and unlock some units, for example for Rohan the guardians of Hama are now buildable in the citadel, for Lotlorien/Mirkwood Border sentries and Mirkwood spearman are buildable Border guards are good against monsters and archers and have a good speed while the mirkwood spearman are a unit to defend they are good against cavalry and have a shield formation making them good against infantry, they can be limited or cost to much CP or resources, Mordor, Trolls of Dol Guldur can be summoned pemanently by an external spell or buildable, they are limited to three but they are to powerful, Imladris Lindon Sentry the spearman they are good against cavalry, monsters and infantry, Angmar an Ice Balrog or the beast of Udun can be summoned pemanently by an external spell, of course it wont be OP, Gondor i dont know maybe an upgrade with a new armor to the infantry, Dwarves Durin maybe.
Or maybe make these units can be an permanent external spell of the palantir after unlocking all spells or having 35 points.
This idea was because some elements and units of the Hobbit and the old version of Edain are missing in the game and it would be nice to having them back not only for some seconds, it would gave more flavor and to the battles.
2. Gave a shield to the lothlorien infantry or a light armor upgrade to them its because its a little boring having them without an armor.
3. Make the AI able to build werewolves and fellbeasts
4. Change the stance of spearman, in Total war the spearman are a good unit to defend the ground and in the movies the can be good against infantry so how about if the holding ground stance makes them 50% slow but gain more damage or armor against infantry, aggresive stance they gain more damage against infantry but they are more vulnerable to trample or flanking damage and the normal stance, this isto make the a little more interesting and having a better role for them for example the tower gards and the normal spearman the spearman can be more agile and maneuverable against infanry while the tower guards are more slow and tanky, and this is a good way to implement the mirkwood spearman, its because i love them in the movie they are great
of course the palace guards would be more expensive an the complete batallion could be limited to three or something like that.
5. Make the units fly a little more when they are knockback, (its more fun XD)
6. I would like to see the chariot and the ballista of the dwarves maybe not like the movies but able to send flying units ( yes i like to send flying units) or maybe it could be the new siege weapon for imladris
7. In maps like Minas Morgul, Dol Ugldur you can build the specific orcs and specific spells for the map, this can apply for other factions too.
8. Gave gondor or arnor the nightwatch horn it would be so epic.
9. Have a dinosaur easter egg (Spinosaurus or T-rex)
Well those were my ideas i hope you like them and it could be considered, at least the implementetion of the units would be great to see it, well thanks for your attention and sorry for my english.