|I hate those stupid anime/GW oversized weapons.|
A +1 weapon, instead of just adding +1 point of damage, the player would roll +1 damage die, and choose which of the two results to use. A +2 weapon would add two dice, and so forth. A character wielding a +2 longsword would get to roll 3d8 instead of 1d8, and could choose the result showing on any of them. A +1 dagger would roll 2d4 instead of 1d4, and so forth.
Just to clear up any misconceptions: you DON'T add all the dice to get a damage result, you CHOOSE ONE of them.
I should note that I have done absolutely no statistical analysis to determine how this might affect damage infliction rates. At this point, it's just a brain-fart.
I guess it should work well enough for cursed weapons as well, except that the player would lose the element of choice and would always have to take the worst result, normally the lowest.... but if, for example, attacking a friend while charmed, it might be the higher.