Unisystem works like this, in Cinematic anyway. Weapons have a set damage, or are a multiple of strength. So a gun might do 16 damage, while a punch does 2 times strength. There's also modifiers to damage types, so a bullet does double damage to living targets for instance. Then you add on a bonus based on how well the attack was. So if you shoot someone with said pistol and get 4 success levels (a very good hit) you do 20 damage. 40 if they're a living target.
Classic you can roll for damage, but there's still the option to just use the standard damage. I like it myself, it makes combat a lot faster and smoother.
And the real reason weapons do different damage types? Because when Gygax & co found a place to sell d20s, it was from a mathematics supply company and they only sold them in sets. So they had the d20s and d6s, but they also had all these d12, d10, d8, and d4 dice. Rather than throw them out, they decided to use them for something!
Classic you can roll for damage, but there's still the option to just use the standard damage. I like it myself, it makes combat a lot faster and smoother.
And the real reason weapons do different damage types? Because when Gygax & co found a place to sell d20s, it was from a mathematics supply company and they only sold them in sets. So they had the d20s and d6s, but they also had all these d12, d10, d8, and d4 dice. Rather than throw them out, they decided to use them for something!