Swadian Macemen should be fairly effective against heavily-armored troops; their weapons aren't doing Blunt, they do Pierce.
Most maces in the game do Pierce damage and as most of the long-term players know, certain weapons like the Manhunter's Polehammer are really very close to perfect weapons. This more-or-less reflects my research about these arms.
IRL, maces in the later Middle Ages were built around the concept of concentrating as much force as possible into a small surface area. The classic flange maces, for example, were designed to concentrate the majority of a well-aimed blow upon the tips of the flanges. Tests with these weapons indicate that they were capable of piercing plate armors to some degree, but were excellent at transmitting blunt force trauma into the target.
So if Swadian Macemen suck, the issue is probably one of reach or armor; their weapons should be really deadly for assault battles or encounter scenarios where reach doesn't matter much, like when you take a stacked infantry line and collide it with an enemy infantry charge.
Where Macemen aren't terribly useful is against heavier cavalry; there reach plays a pretty big role and you'll want spearmen, halberdiers or pikes up front, macemen a pace or two behind to kill cavalry that penetrates the front line. The opposite formation can be extremely dangerous vs. infantry with two-handed swords, as the maces block quickly, the macemen get shields, and the polearms can still strike.
@Epicrules: Spearmen and pikemen who don't have grenades and are stacked (use Stand Closer 4X or more to form a phalanx-like formation) do very well against cavalry for cost, imo. The main issue with them is that they really shouldn't be kept with infantry that uses swing attacks- that type of infantry generally does better in a looser stance, whereas spears do better with a tight formation. That, and unless the proportions are right, cavalry will go around the flanks a lot. A great tactic is to have troops with two-handed swords, axes or slashing polearms in a second line with a stacked unit of pikes in front and missile troops behind; that's a pretty efficient horse-killer and it tends to mulch most infantry very effectively.