First off, I'd like to say great mod, you've obviously put a lot of tie and effort into this, and it shows. I've been playing a round as the Undead, and I have to say, it feels very true-to-life in that whenever I go to war I end up with an army of ghouls that I can use to swamp the enemy with numbers. Of course, one time I moved a stack of them into a mountain tile, unaware that the enemy had some invisible units there, so that wiped out about 3/4 of my stack of around 12 ghouls, which also seems kind of realistic, as a horde of zombies marching unknowingly to their death.
Anyways, the amount of free ghouls helps make up for the relatively weak quality of my troops. I'm only midway through the scond era, but I've found keeping Dark Riders back to bombard a city from a far while having a stack of ghouls escorted by a Death Knight or two to be a very effective method of conquering territory. Of course, after my stack was mostly wiped out, I had to quickly teleport Myst Warriors from overseas to help replenish the ground troops, although their weak defense makes providing an escort mandatory for them.
Another thing I've found interesting is the difficulty in building up infrastructure. The Tomb Crawlers are fairly expensive, as well as costing 2 population, making it hard for some isolated cities to build them. Of course, they are extremely useful, being able to both settle as well as work tiles, but I'm not quite sure that I wouldn't be better of with two seperate units for settling/building. Of course, that may have been the point. Another two-edged sword are the invisble ships. The AI accidently starting a war by running into them is slightly annoying, and there aren't any visible ships to provide escorts to hel pprevent this. Still, I think I prefer this to remain the same.
Anyways, great game, my only minor complaint is how leaders produced by combat seem to upgrade to Maniacs for every single race. It just seems wrong having an axe-wielding barbarian fighting alongside the hordes of the undead. Having race-specific upgrades for leaders might make things a lot more interesting, in my opinon. Although that might mean a lot of work, but also a whole new creativity process as to what abilities the leader might have.(ex for the undead maybe an undead horde unit with extremely high hit points but only average combat stats, while the Burning Legion might have a unit with an extremely high attack but vulnerable on defense, etc)
Anyways, just some of my thoughts, and once again, great mod.