I should like to mention, that if the tactical battles are supposed to be very similar to MOM there are a couple of elements to MOM that seem to have been left out that match up with some of the concerns:
1. In MOM all units DID counter attack. They counter attacked as many times as they were attacked in melee. Lest you think this was overpowered, the main advantage of attacking was the order in which attacks happened. Additionally, there were a few abilities in the game that allowed no counter attack.
2. The main importance in MOM tactical battles was the order in which attacks happened within one round of combat. when one unit attacked another, all special attacks and abilities happened first and did casualties, and then the regular combat happened, and then after taking casualties the defender got to hit back. The order was very specific so breath weapons first, then gaze attacks, then first strike, then thrown weapons etc. One of the main items of importance though was most special attacks only worked when you were the attacker.
The tactical combat in MOM had quite a bit of depth actually but the depth didn't come from the movement system as much as how abilities played out against each other. Zombies were horrible but cheap and completely immune to illusionary soldiers. Those illusionary soldiers cut right through regular units though because they ignored defense values etc. Movement types could be especially important since non-flying units could not initiate combat rounds with flying units unless they had a ranged or throwing weapons, phased units could walk through city walls etc.
If you can get your hands on a MOM manual or especially the strategy guide, there's a lot of good, in depth ideas in there, that are explained in extensive detail. One of my favorite parts of the tactical game was the huge range of abilities and how they played out against each other.