Here's my brainstorming for a more detailed melee combat system:
People have 3 stats, that I'll call Breath, Balance, and Blood for the amusing alliteration.
--------------------
Breath represents how physically tired, out of breath, physically capable you are of doing fighting related actions.
Like swimming as fast as you can, melee fighting is something that uses many muscles in the body at once and can make you tired/ out of breath very, very quickly.
A disadvantage of armor is that it tends to increase the breath cost of actions. Well fitted armor generally doesn’t stop you from doing stuff, but it certainly makes you tired faster.
Being out of breath restricts the ‘size’ of maneuvers you can do. It’s much harder to make a powerful attack when you are gasping for breath, but you may be able to manage poking someone in the eyeball.
Starting breath would be based on your physical fitness/endurance stat, possibly with a modifier for how tired you are, in general.
----------------
Balance represents how well positioned you are to make and defend against attacks.
You generally have to use up balance to make attacks and to defend against them.
In general, the stronger the attack, the more balance you have to give up to make it.
Defense works the same way, the stronger your defense, the more balance you have to give up to make it. This is the advantage of armor, it allows you to make a weaker defense (which costs less balance) to mitigate the attack down to something you armor can take.
Being out of balance means that you are probably doomed, people can make powerful attacks against you, and you don’t really have any ability to defend against them. Also, you can’t really make attacks in return. So things like getting knocked down, or having your weapon pinned can really ruin your whole day.
People who don’t’ know how to fight generally have low balance scores, they have no idea how to attack or defend. Once you get to a modicum of competency, your balance score mostly stops going up, after all both you and the ultimate master stand in almost the exact same fighting stance. But as you get much better at combat, actions with a balance cost become cheaper to do
So, despite armor making your actions take more breath, it’s generally easier to defend yourself if you are wearing armor, because you don’t have to put as much effort into your defense.
----------------
Blood, this represents how wounded you are.
Small wounds generally reduce your breath, while large wounds can reduce both your breath and your balance. Some wounds bleed, which increases the amount of the penalty you take from them over time.
Being out of blood pretty much means you are lying around, waiting for someone to put you out of your misery. But maybe your friends will come along before that unhappy event happens, or your opponent will decide to take you captive instead.
Note that blood doesn’t necessarily show how close you are to death, for example a broken leg would give you grave penalties to balance, but you aren’t going to die from it in the next few minutes.
--------------
Damage
An attack can damage any of your three stats, or it can kill you outright.
Examples:
In general, fighting people with your fists and feet does mostly breath and balance damage. It’s hard to kill someone outright with your fists, normally you have to do something like beat them down and strangle them. Of course, some attacks, like say, gouging someones eyes out can do blood damage, but they tend to be rarer.
Certain attacks, like tripping someone or knocking their weapon out of line do almost all balance damage, the attack is designed to make following attacks easier, not to damage the target outright.
Same attacks, like getting trampled by a horse, are so massive that they do damage to all three stats.
---------------
Timing
There are four important times
1. when you decide to do something
2. when the other person can notice you doing that thing
3. when the thing actually happens
4. how soon you are able to do something else afterwards
So, a feint would be a move that looks like another move, but there is also time that it becomes obvious your move is a feint.
Interesting side effect: it also becomes possible for two opponents to kill each other by both committing to offensive moves that leave them no defensive options and land close together.
four things matter for timing
1 how fast you are able to get your body to move
2 how well you can notice something is happening
3 how fast your mind can process what it sees, and act on it
4 how light or maneuverable your weapon is.
-----------------
So, powerful attacks are generally a bad idea, for the following reasons:
1 They cost a relatively high amount of breath and and balance to make
2 They are well telegraphed, your opponent can see them coming, and has a lot of time to do something about them.
But, they are the attacks that do massive blood damage, or end the fight all together, so it’s the powerful attacks that we actually want to land.
How do we get our powerful attacks to land?
run the other guy out of breath and/or balance, so that even though he can see the attack coming, there’s nothing he can do about it.
Or use small attacks that do blood damage to bring him down that way.
Or exploit you opponents timing such that you can land an attack and there is nothing they can do about it.
-----------
So, sample fight:
--------------
Unarmored guy with huge axe vs unarmored guy with rapier:
Guy with axe: I wind up for a huge, powerful attack.
Guy with rapier: I see it coming, and have all the time in the world to put my sword into your eye before you axe can land.
Guy with axe: alas, I am dead! But you are no so fast with the rapier that you can act fast enough to prevent my axe from cleaving you in twain, even though I am dead.
Guy with rapier: whoops. Maybe I should have been a bit more conservative in my life choices.
-------------------
Of course, the really hard part ti figuring out timing, costs, and damage so that there are no simple paths to victory...