scribbler
Warlord
Well, from a RL POV spearmen were nearly useless against horse unless they were very well disciplined and stayed in ranks. Granted, any military unit of the pre-rifle era that formed and could keep ranks was formidable on the battlefield, but the catch has always been that forming and keeping ranks is ninety percent training and ten percent experience. Same with pike and phalanx.
But Civ IV is horrible at dealing with these exceptions. In fact, I can think of dozens if not hundreds of other exceptions that should be but aren't in place. Horse archers, for instance, should be practically immune to everything but archers, faster horse mounted units, and their own hubris and excitement for battle. That's the reason why the Mongols were so effective. Of course, just having a killer unit isn't enough, as the fall of the Mongol empire showed, and keeping that high level of training and ability around is just as hard in its own way as keeping the training to form and hold ranks.
Only running up against infantry with strong enough shields to stop their arrows, which the infantry are well-enough trained to use (not an easy thing to accomplish) would mean either getting in close (and getting hurt in the process) or having almost no affect.
