0AD gameplay is not that geared around counters, but anyway, this is my input based on tactical use more than on simple performance:
- swordsmen are better than spears against other infantry, but you better have spears or pikes if you fear a cavalry attack.
- in almost all cases, pikemen are the best melee infantry, because they soak damage better than the others, and in infantry clashes most damage is dealt by ranged troops.
- skirmishers are OP, they are not really countered by