Light Plate mail was developed to counter the threat of Longbows and the crossbow was developed. Heavier plate was ultimately countered by heavy crossbows.
One additional Caveat with this. The crossbow was not expressly designed to "puncture plate" as the metalworking techniques of the time were unable to create practical metal armor thick enough to protect against a properly angled arrow (hence all the angles on later era plate) from a normal longbow. The benefit of the crossbow was more that you could slap one into a peasant's hands with a quiver of bolts for training and they would have a reasonable time taking down the knights since they were also up closer and more expendable. Proper longbowmen took months of training to become effective. So, while Crossbows of the time DID have a slightly higher force exertion behind their shots, they had dramatically worse range and no significant benefit over the longbow aside from training time. It was the NUMBER of crossbows on the field that killed the armor knight (so to speak) rather than the science of the device itself.
Back to Topic:
The discussion over greater differentiation of weapons is very valid. Particularly how there really isn't a strong reason to not just use hammers in plate for your defenders and spears for your cheap and cheerful mobs. A big part of that I think stems from our weapon choices and how you differentiate them beyond simple flavor.
* Daggers are cheap and fast, and honestly not really all that practical on the larger field of battle. In current in game incarnations, beyond the +initiative bonus, I have yet to feel that even the most powerful dagger I've found was worth using over a Boar Spear (which we will get to).
* Staves are cheap and useful tool and weapon which are more for personal protection than offense (a defensive weapon, if you will). In game, they are what you get for free on your sovereign and hope you never have to fight with because they never do more than 1 damage against anything. No legitimate reason to ever purposefully put these on a unit.
* Clubs are cheap things you can turn any tree branch or table leg into. I think they are perfectly well represented in game.
* Hammers are slow and hefty. In history, great against armored foes because of the ability to cave in plate armor, crippling the enemy, and possibly causing their armor to be the death of them. In game, 1 handed decent quality weapons with good damage output.
* Swords were all around utility weapons of varying lengths and styles, relatively fast weapons with a general focus on finesse. In game they are..... Different looking than hammers with less damage output and not enough + initiative to make a difference.
* Axes are large, brutal weapons used for severing limbs and turning forests into cities, slow and deadly. In game they are.... Different looking than hammers with a slightly lower initiative penalty, and the occasional awesome ability you get to use too late (I'm looking at you berserker axe).
* Spears were cheap weapons that were easy to train and put into the hands of conscripted men to help use numbers to offset skilled opponents and cavalry. In game they are cheap early game weapons that ignore 66% of an enemy's armor and don't use much by way of materials. No legitimate reason to NOT put these on your mass units.
What we really should see are things that make these other weapons worth taking. Frogboy said himself that Champion traits are pretty well trivial to program. How difficult would it be to add unit traits that they can *elect* to purchase but only when built with a certain weapon? Howabout giving all weapons one static "you use a sword so you get THIS ability" and then 2-3 other abilities tied to that weapon?
Make "Armor Piercing" a 2 turn respawn ability for all spears, and give them a 10/20/30% native AP rating for spear/boar spear/pike
Give hammers a knockdown or stun ability option
Give axes the ability to cripple a unit's strength or initiative on a failed resist (with damage either way, of course)
Let units wielding daggers have some manner of "cloaking" so they cant be seen until 2 tiles away, or the capacity to totally ignore armor once per combat.
Give swords an ability that attacks twice at full strength
Give staves something ANYTHING to make me not horrified that my sovereign has to use it. +1 Counter-attack for additional damage perhaps (like 5 points?)
Give ALL non-magic ranged units a limited number of shots per battle. They aren't exactly unbalanced, its just that with unlimited shots there's no reason not to kite if you can. Also, this lets you give players the option of taking the "Extra Large Quiver" feat to add 2 shots, and add production cost and weight to their units.
I don't think that the numbers are off on the weapons, per se. It's just that we really don't have a compelling reason not to just go for "highest DPS" and "Highest DPS for cheap".