You could use some physics to create weapons (I'm not talking about game physics engines, but science physics). The idea is that weapons do damage based on certain physical properties of them. As an example, a blunt object does damage based on its deceleration (after it hits the target).

Of course such physics calculation can take a fair amount of processing, and you wouldn't want to calculate this for each swing of the weapon, but you could do it when the player creates the weapon as a generalised factor for determine the amount of damage (per-calculate it to a single number that can be used as the damage number). It doesn't have to be precise for each hit, but you can just use a range and pick a random within the range.

Using this, you would get weapons that have long handles and a heavy mass at one end. This means to balance it, you need to have some mitigating factors. The first is that because the character is applying a torque to the weapon, then the more massive the weapon is (and the longer the handle) the slower it will be to use, thus the player has to balance between a slow but powerful weapon, or a fast but weaker one. They would need to find (or make) the best length for the handle and find just the right mass for the head.

Another factor could be durability. Each hit could potentially cause damage to the weapon itself and over time it could risk breaking. This would make the player need to repair it (replace the component(s) that are becoming weak). You could then have objects that can be used to increase the structural integrity of the object, making it less likely to break, but making it heavier (and thus slower) without increasing the amount of damage done.

Puncturing (stabbing or slicing) weapons are harder to simulate but there would be ways to simulate this too.

As for actual damage, there are really two types of damage that get done in an injury: Trauma and Bleeding. Trauma damage is immediate and disabling damage and blunt weapons would do a lot of this. However, bleeding is perhaps worse over a longer time as it continues doing damage over a period of time and puncturing weapons would do more of this.

The idea now is to find a way to balance between puncturing and blunt weapons. If we treat Trauma as a temporary damage and bleeding as slow (but permanent) Damage over Time, this gives us a framework with which to balance them.

So when a player gets hit, the trauma damage is applied immediately and is slowly reduced over time and bleeding damage is applied slowly over time. Blunt weapons are useful to quickly take down an enemy, but it might mean that they will get back up. If you use just a puncturing weapons, then it could take some time to drop an opponent, but once hit they will constantly loose health until they stabilise or are healed. Thus if you use a blunt weapon to drop an opponent and finish them off with a puncturing weapons, then they will not be able to get healed before their health drops to a critical level and they die.

With bleeding, it should be harder and harder to increase the rate of bleeding, but instead make subsequent hits decrease the chance that the target will be able to stabilise and prevent further bleeding. So multiple hits with a puncturing weapon make the target bleed for longer, but not necessarily at a much greater rate. This also give a different use for first aid, that instead of just giving back health or just reducing the rate of bleeding, it instead increases the chance of stabilising.

However, as even blunt weapons would do a bit of bleeding damage (internal bleeding at least), then even a blunt weapon by itself can take down an enemy and as piercing weapons also do blunt damage, you can still take down an enemy with piercing weapons too.

You could use some physics to create weapons (I'm not talking about game physics engines, but science physics). The idea is that weapons do damage based on certain physical properties of them. As an example, a blunt object does damage based on its deceleration (after it hits the target).

Of course such physics calculation can take a fair amount of processing, and you wouldn't want to calculate this for each swing of the weapon, but you could do it when the player creates the weapon as a generalised factor for determine the amount of damage (per-calculate it to a single number that can be used as the damage number). It doesn't have to be precise for each hit, but you can just use a range and pick a random within the range.

Using this, you would get weapons that have long handles and a heavy mass at one end. This means to balance it, you need to have some mitigating factors. The first is that because the character is applying a torque to the weapon, then the more massive the weapon is (and the longer the handle) the slower it will be to use, thus the player has to balance between a slow but powerful weapon, or a fast but weaker one. They would need to find (or make) the best length for the handle and find just the right mass for the head.

Another factor could be durability. Each hit could potentially cause damage to the weapon itself and over time it could risk breaking. This would make the player need to repair it (replace the component(s) that are becoming weak). You could then have objects that can be used to increase the structural integrity of the object, making it less likely to break, but making it heavier (and thus slower) without increasing the amount of damage done.

Puncturing (stabbing or slicing) weapons are harder to simulate but there would be ways to simulate this too.

As for actual damage, there are really two types of damage that get done in an injury: Trauma and Bleeding. Trauma damage is immediate and disabling damage and blunt weapons would do a lot of this. However, bleeding is perhaps worse over a longer time as it continues doing damage over a period of time and puncturing weapons would do more of this.

The idea now is to find a way to balance between puncturing and blunt weapons. If we treat Trauma as a temporary damage and bleeding as slow (but permanent) Damage over Time, this gives us a framework with which to balance them.

So when a player gets hit, the trauma damage is applied immediately and is slowly reduced over time and bleeding damage is applied slowly over time. Blunt weapons are useful to quickly take down an enemy, but it might mean that they will get back up. If you use just a puncturing weapons, then it could take some time to drop an opponent, but once hit they will constantly loose health until they stabilise or are healed. Thus if you use a blunt weapon to drop an opponent and finish them off with a puncturing weapons, then they will not be able to get healed before their health drops to a critical level and they die.

With bleeding, it should be harder and harder to increase the rate of bleeding, but instead make subsequent hits decrease the chance that the target will be able to stabilise and prevent further bleeding. So multiple hits with a puncturing weapon make the target bleed for longer, but not necessarily at a much greater rate. This also give a different use for first aid, that instead of just giving back health or just reducing the rate of bleeding, it instead increases the chance of stabilising.

However, as even blunt weapons would do a bit of bleeding damage (internal bleeding at least), then even a blunt weapon by itself can take down an enemy and as piercing weapons also do blunt damage, you can still take down an enemy with piercing weapons too.

That's a good idea for damage. I'm probably going to make the owned weapons be just basic weapons, but the pickups are more specialized, and can be used inderectly. For example: you could throw a small rock to knock out a stick holding up a boulder, or some kind of thing like that where you wouldn't be able to use one of your melee weapons because they can't be thrown, and an arrow would be so skinny that you would have a hard time hitting it. They would basically be disposable weapons.