I'm going to wait for the second release before I download...
Some pointers as well as some constructive criticism:
1. The ring piercings on Xerxes are too bright, try to tone the color down and match it up with the scene.
2. As previously mentioned, the archers need to be grabbing for their bow before they shoot.
2.5 The attack for the archers needs to be more fluent. It seems that for every one shot, he returns to his original position. If the battle last long, then he will do this a number of times which is unrealistic.
3. The Immortal Horseman need to be going through the motions of grabbing an arrow, then pulling the bow back before he shoots.
3.5 The spartan horse shouldn't be bobbing his head up and down during the attack. The spear should be driven from the side of the horse, not above its head. Same goes for the Immortal Horse. The bow should be just off to the side a bit, so the the horse's head does not get in the way.
4. The Greek swordsman his looks like he is lunging his sword forward like a spear. Make him attack like a real swordsman.
5. You might want to add some fidget animations to spice things up a bit.
Hope you take some of my suggestions into consideration. Other than that, great idea, great effort, surely this MOD will work its way to being very popular!
Polyphemus