Osbot,

I suspected as much, although I've not faced much yet except for the Numidian cavalry (and they really tear me up unless I have lots of cav.) I've not yet gotten to Eastern factions. Most of what I've read indicates that missile units alone were not all that effective vs. phalanx. They could wear them down over time, but it was far from quick. I've been bothered by the high kill rates of my own missile units. Slingers seem about as effective as arbalesters were in MTW. I really dread seeing archers on the field and so far have only faced a few units. I generally sacrifice a cav unit or two to chase them off and kill them.

A combined army should be best of course as Alexander and Hannibal proved (and Scipio adopted), but in this day and age (before crossbows and stirrups) heavy infantry should be relatively hard to crack.