Now that I'm back in the US and can access my old RPG materials I've been re-reading "The Slayer's Guide To The Undead" by Gary Gygax. I'm currently reading the sections on zombies and skeletons and how they can only respond to commands in the most literal of ways and are incapable of any sort of intelligent self-guided action. There's a funny line about how the necromancer might make a grand gesture and order his skeletons to "kill them!" and end up indicating a bunch of his allies by accident along with the PC adventurers.
Being a necromantic military commander would be a fun concept for a RTS game. The way I see it, it would be a bit like the game Lemmings where your zombies would just keep doing what they were last told to do, potentially walking off cliffs or going into suicidal situations. Part of the challenge of the game would be quickly re-issuing orders in response to changing situations and the discrepency between the situation changing and the rate at which the player can issue commands with the mouse. I am imagining having a decent RTS style artificial intelligence for the computer opponents, which would be the humans or the elves or something, and having that contrast with the dumb-as-bricks zombies which the players control.
I can see the concept as being more effective with touches of humor to go along with the potentially frustrating stupidity of the zombies. Perhaps the player plays the role of a busty female necromancer with a spiky leather bikini and the ending graphic shows her sitting grinning on a throne with a big cup of wine and some totally humiliated paladin holding the wine jug, or something.