excellent post regarding the d6 as the arbiter of weapon damage. I agree with much of JB's thoughts although I have a twist on it which I am using in my ROGUISH RPG.
I believe there should be at least some sort of subtle difference between daggers, spears, sling stones, battle axes and long swords. Yet I do not want to use multiple dice types (ROGUISH is d6 only) nor have everyone running around with the same weapon because it does X damage.
So how to make them interesting and different while using d6 only? I decided to create damage classes.
(L) Light damage = roll 2d6 keep the lowest number rolled
(M) Medium damage = roll 1d6 use number rolled
(V) Heavy damage = roll 1d6 and use highest number
(X) Extra Heavy damage= roll 1d6 and add +2
Weapons, monster attacks, and spells all use this simple short hand notation (L, M, V, or X). So if you like the idea of d6 weapon damage but want to keep a bit of difference between weapon types, this might work for you.