On the upside:
# - I like the 'capture base' idea where you secure your base with the circle of power. helps against rushers!
# - bases are big enough (well, Mirkwood was!)
# - Lots of races with many units and spells, good variety!
however, as you said, it needs some fixing. Here are some things you might want to take note of:
# - why are Roadway Towers so expensive?
# - map missing Helm's Deep, unless i'm seriously mistaken...
# - how do merchants work? where are these 'trade goods'? does he sell them automatically?
# - map needs a model/skin makeover (I played as elves and all the archers are women, even Legolas. There are some good male archers in skins & models here on THW, also the Baradur Tower (Mordor Tower) is here too)
# - check existing doodads. (E.g. in the base on the left, south of Gray Havens, i think?) the wall/battlements ('low wall's' on cliff edge) are sunken into the ground)
# - maybe split up the hero start locations more, so people don't start together
# - why are there meteor's falling onto Osgilliath?
# - this map is huge, maybe consider implementing the 'squad system' to better control armies (it's here on THW, in 'Spells' i think...)
Some terraining suggestions:
try brush over large patches of the same terrain with a different kind of tileset to break it up a bit. (e.g. in Mirkwood, use other types of grass ontop of the current grass, think camouflage patterns!) [Note: this is not gonna be fun to do, but it will be worth it!]
add more doodads, (rocks, grass, bushes, single trees etc) the terrain is a bit bland. (download a UTM map and import some more doodad models or download some doodad packs. change the trees, definitely change the trees!)
'Randomize' height field more, Middle earth seems a bit flat... (e.g. make hills leading up to mountains)
Make use of regions and weather effects. (do this to add effects as opposed to making meteors and lightning in Mordor)