Infantry are fine for the most part. They have two main problems.
Pre-Squires Speed
The first, and arguably the most important, is that they cannot be used from mid-feudal until late castle age, because archers are faster than them and hard counter them. Since archers can chase down Infantry, they have no choice but to retreat to safety, and stay there indefinitely.
This means that they lose what SHOULD be their biggest strength; being able to mass them prior to hitting Castle Age. Lacking that, players need to make 50% more Barracks than Stables to keep up production, which makes them a non-option in early castle age, too.
By the time you’re at late Castle, your enemy has the eco to make a quick swap into archers if you choose to go for them.
By early imperial age, population efficiency takes the lead, and since you need a 2v1 advantage to win vs cavalry, you can’t go infantry there, either, because you get pop capped and can’t compete with more population efficient units.
Only in late Imperial do they once again become an option, as gold starts to run out and trash becomes more common - but by then, you’ve got something like 6-8 techs to research to get into them, which makes the transition difficult or impossible.
But, consider what happens if you give them Squires earlier.
Feudal Squires
If you give them Squires in Feudal, then they can escape Archers, where they could not escape before. This means that rather than being forced to retreat all the way home to safety(or just die) they can run away out of LOS and escape, allowing them to attack again, and again, and again. They can’t beat archers at this stage, but they can at least survive, and harass your enemy. Probe from one direction, then another; deal damage to buildings, force repairs, cause villager idle time. This reduces enemy aggression and disrupts their economy, paying for the early investment into Squires.
Going into Castle Age with an existing mass of infantry means you can outmass the first Knights to come out, and, if you go for Longswords, even win that fight. If your enemy takes a bad fight with your longswords they could end up a few minutes into castle age with practically nothing, perfectly setting up the longsword player to win.
This also forces your enemy to play more cautiously, because Longswords can tear down walls and buildings faster than anything shy of battering rams in Castle Age, and if they try to send all their army forward, they might get hammered from behind.
This carries longswords all the way through to late castle age and even early imp; at this stage, population efficiency will provide natural counterplay and force the Infantry player to do something else, but that’s fine; all they have to do then is survive for long enough that gold runs low, and their existing techs will make a re-transition into infantry far more viable in the lategame.
Making squires available in the Feudal age is the answer to problem number one.
Problem number 2: Pathing
The second problem with infantry is Pathing. Because they are individually weak, they rely on getting multiple units into the fight at once, but while an army of knights might be 1 or 2 units deep, an equal army of infantry will be 3-4 units deep. This means they need to path around each other to even engage in a fight, and it means that equal-resource fights between, say, 5 knights and 1 longswords, will almost always favor the longswords, but 10 knights vs 20 longswords will almost always favor the knights.
The only way to correct for this at present is to abuse formation-switching to stack infantry on top of each other, which obviously isn’t ideal.
The answer is pretty simple; just reducing the size of the Militia Line(not their model size, their collision hitbox) by something like 15-20%. This is enough to make sure they at least can trade evenly with these enemies.
After that, it’s just a matter of making sure you’ve got the existing units after hitting Castle Age to make those favorable trades.
So, to sum up:
- Move Squires to Feudal
- Reduce militia pathing size by 10-25%.
Problem solved.