Bugs:
jeweler (item shop) can be ordered to move (as red)
attack and armor upgrades done at the Circle don't affect troops
Tips:
the Minas Tirith city is way too tiny for a map based on defense. Make it way bigger, add lots of citizens (which need to be protected to win), guards, not chosen heroes as NPC characters, multiple attack paths, and bigger waves of enemies.
Add some more realism (battles like in the movies) by adding friendly fighting forces, customization of those forces, and setting up barricades/towers/catapults.
Gems of Shadow and Gems of Death don't fit to be used by humans that are not evil. It just doesn't make sense.
Suggestions for Recipes
Recipe+Iron shield+2xreinforced armor--->Oaken Shield- Grants some armor, a health bonus, and a chance to reduce incoming attack damage.
Recipe+Quarterstaff+Gloves of Spell+Gem of Ice--->Great-ice Staff- Grants intelligence, attack damage, armor and the ability to cast a Frost Nova.
Recipe+War Axe+Gauntlets of Strength--->Headcleaver- Grants lots of damage, some Strength, and the Bash ability (doesn't work on bosses)
Recipe+Iron Sword+Ruby+Necklace of Iron--->Moonlight Blade-Grants a bonus to damage, life regeneration and gives an active ability that increases attack speed for a few strikes.
Recipe+Iron Shield+2xDiamond+Soldier Helmet--->Guardian Plate- Grants lots of armor, health and life regeneration. Also grants a small armor boost to nearby allies.