So this is pure theory crafting, since actually implementing this will drastically shift meta. Note that I mentioned Barracks rework, not Infantry rework, since many infantry UUs are fine, but we shall touch on them for sure.
Firstly, the Barracks will have 3 unit lines - which are the same as current. It will have two technologies - Squires (Castle Age) and Arson (Imperial Age) with same effect. You may want to replace Arson with something more interesting.
Unit lines -
- Spearman (ROF 2, cost 40F 40W, speed 1, type - infantry, armors - 1 melee, -2 pierce, 0 infantry). Spearman armor dropped and unit is given negative pierce armor.
- Scout infantry (basically the eagle scout line) (ROF 2, cost 40F 40G, speed 1.1, conversion resistance, type - infantry, armors - 0 melee, 0 infantry)
- Long Swordsman (ROF 2, cost 50F 20G, speed 0.9, type - swordsman infantry, armors - 2 melee, 2 pierce, 0 infantry)
Dark Age -
- Spearman - 45 HP, 3 melee, +5 vs cavalry, +4 vs camels attacks
Feudal Age -
- Pikeman - 50 HP, 4 melee, +10 vs cavalry, +8 vs camels attacks
- Scout infantry - 50 HP, 2 pierce armor, 4 melee, +6 vs Monks, +4 vs Siege attacks
Castle Age -
- Glaiveman (current heavy pikeman) - 55 HP, 5 melee, +15 vs cavalry, +12 vs camels attacks
- Light infantry - 55 HP, 3 pierce armor, 6 melee, +8 vs Monks, +6 vs Siege attacks)
- Long Swordsman - 60 HP, 8 melee, +4 vs Standard buildings, +4 vs Infantry attacks
Imperial Age -
- Halberdier - 60 HP, 6 melee, +20 vs cavalry, +16 vs camels attacks
- Two-Handed Swordsman - 70 HP, 10 melee, +5 vs Standard Buildings, +5 vs Infantry attacks
- Champion - 80 HP, 12 melee, +6 vs standard buildings, +6 vs infantry attacks
Native American civilizations will have a regional upgrade to the Light Infantry - Eagle Warrior. 60 HP, 1 melee, 4 pierce armor, 8 melee, +10 vs Monks, +8 vs Siege attacks, 1.25 speed
Other complementary changes - Cataphracts 8 cavalry armor, Elite Cataphracts 10 cavalry armor (to negate 50% attack from spear line). Parthian Tactics does not give variable attack bonus vs Spearman, rather gives +2 attack vs Infantry.
Swordsman units will have atleast 2/1 or 1/2 armor in Castle Age and 2/2 armor in Imperial Age. These are slow moving units resistant to both melee and pierce attacks, and have speciality against light units (eagles, sears, light cavalry), buildings and camels usually.
Other swordsman units:
- No changes needed - Teutonic Knight, Obuch, Serjeant, Throwing Axeman, Kamayuk
- Samurai - can switch between ranged and melee mode. Stats identical to Long Swordsman and Two-Handed Swordsman. In ranged mode, have 4/5 pierce attack without attack bonuses. Maybe 2/1 armor in non-Elite form.
- Urumi Swordsman - attack bonus vs infantry replaced by charge attack. Current armor and movement speed modified to match the swordsman standards.
- Dismounted Konnik - add 2/1 armor, lower the attack to 8/12 melee
- Jaguar Warrior - same stats as Long Sword line but attacks ignore armor
Ambiguous units:
- Woad Raider
- Berserk
- Huskarl
- Flemish Militia
- Condottiero
What do we achieve?
- The Spear units are almost the same against cavalry. Their attacks come in 50% faster, but are equally nerfed as well. Their melee attack is significantly boosted by 50% faster attacks and so is their melee armor, hence increase in cost. Rather than units have variable attacks vs spearman armor class, the unit is itself adjusted to have -2 pierce armor since that is what most ranged units do. Against infantry, their attacks come in 50% faster and have +1 armor, but this offsets the attack bonus they had against eagles and the attack bonus they will receive from Swordsman infantry. Overall, the unit will perform similar against all units except Villagers, Monks, Siege, etc.
- The scout infantry fills in the role which is needed to make infantry viable - raiding. Unlike its mounted counterpart, it costs gold. Infantry civilizations with poor cavalry can now have an answer to monks and siege, and somewhat archers. Examples - Dravidians, Goths.
- The Swordsman line is weaker in attack vs non-infantry units but much stronger in armor, just like the Obuch (which is a very viable infantry). It fills almost the same role, as anti-trash, anti-eagle and anti-building, while probably being weaker against camels. Rather than being at the forefront and most important Barracks unit supposedly, it enjoys a much passive counter role.
Drush - New spearmen vs Old Militia
- Pros: Spearmen have 1 melee armor and +5 vs cavalry, so they cannot be fought with villagers or scouts. They are also 11.1% faster. Drush hard counters scout opening.
- Cons: They have -1 attack, so against villagers with loom, they need 20 hits instead of 14 hits. Instead of spending the useless 50 gold you start with, you will need to spend wood which will be needed for other purposes. These units even when upgraded to Pikeman, will not be able to kill buildings.
Scrush - Old Spearman vs New Spearman
- Pros: Can be created in Dark Age itself. It has +1 melee armor.
- Cons: Does 8 damage every 2 seconds instead of 18 damage every 3 seconds. The new Pikeman does 14 damage every 2 seconds, but needs an expensive upgrade. Costs +33% resources.
Overall, the matchup is less polarising. The equivalent of Bloodlines upgrade exists for the infantry too.