First of all, what's Age of Men, what it does and what differs it from many other BFME 1-2. Well, Age of Men is a mod for the upcoming Battle-for Middle-earth: the Rise of the Witch-King. It's not a Total Conversion, but in my mind is the today's biggest non-TC BFME-mods.
— The naval warfare will be deeped by the special Naval-mode (available on special sea maps), where all races will have their unique ships, the Gollum will be swimming in water in his boat and the capture of the One Ring gives you the unique for each race Ring Ship.
— 3 totally new factions: Rohan, Harad and Northern Kingdom. Each with its own tactics, weaknesses and original gameplay-style.
— Each race will get its own Ring Hero. For example — Harad will get the Mumak King, Rohan — the Undead King, Goblins — the Spider Momma and etc.
— 3 BFME-1 featured campaigns: the Good, the Evil and RPG-styled journey of the Fellowship of the Ring. You?ll see and command once more the battle for Minast-Tirith, Helm's Deep, Black Gates and many others in new form — the maps will be more total, the armies — more tremendous and the slaughter — like an ocean of enemy?s blood =)
— New Create-a-Heros: Warg Chieftain, Goblin Shaman, Beorn and some others.
— A lot of units for ALL races (of course). All them will be added according to balance and the kind of the race (let?s try not to spoil the game =)) )
— New maps, some of them totally unseen before — isles in the ocean, underground caves…
— New gameplay style: select tech way of your race (in ground mode): to do more improved infantry or beast (Mordor), sorcery or technical way (Isengard), close or ranged combat (Elves) and so on. The tech way is selected at citadel and affects wich units and upgrades you can use during all the rest of the game.
Generally, Age of Men will be some like an unofficial expansion set for BFME2.