Although I already added some thoughts, I'll try to get somewhat more precise in this post.
1. Speed
Base Speed of all weapons needs to be raised by some degree, maybe save for the Two Handed War Axe. Also I think speed should scale with profiency, to imitate the effect of training.
2. Damage
Base Damage needs to be raised. Especially Polearms need a buff to their piercing damage values. However, damage scaling with profiency should be less important than it is right now. It's not that difficult to deliver a heavy blow without training, but delivering them fast and precisely is. Piercingdamage on a sword should NEVER be higher than at a spear.
3. Critical Damage or "Headshot!"
Not that I've anything against headshots in general, what bugs me is, that you get a damage bonus for getting a hit on the head with distance weapons, but you don't get it for delivering a blow to the hat. Also it's quite irritating to have someone with an arrow through the head charge at you in full speed.
Headshots as well as blows to the hat, as far as it's unarmored or only lightly armored, should be basically killing blows. One may walk away with an hatchet in the head, but he's not fighting anymore.
4. Horses
Charge Damage wouldn't be hurt by a small buff. However the most impotant point with these is damage delivered from horseback. To get a 100% Bonus right now is uncommon enough, but in reality the increase would be way higher. I'd suggest to at least double the bonus.
5. Armor
Armor right now isn't specific enough. Chainmail has to be effective against slashing, but far weaker against piercing damage. Also it's effectiveness against blunt damage shouldn't be that high. With leather it's another story. better ability to absorb blunt damage, but more vulnerable to slashing and piercing.
6. Weapon Breakage
Right now I think it's to high. I broke 3 Weapons in a single battle, spear, axe and sword, all of high quality and that's unbearable. If a weapon smith would sell a weapon fpr this price, that breaks shortly after, he'd be dead as soon as one of his customers comes back alive despite of his broken weapon. A tempered sword breaking while slashing down a couple of peasants wasn't of quality at all.