Here's one small rule I've been considering:
When using a shield, ignore any damage roll of 1. Damage is not otherwise reduced.Note that this is in addition to the standard 1 point bonus to defense. It is also in addition to Shields Shall Be Splintered, if that is being used. Off-hand weapons do not get the same bonus. This rule should work with many of the retroclones, but in particular it's meant to compliment some changes I've been contemplating for the combat table.
Background: Although I don't completely buy the argument that shields are underpowered, this seems like a simple way to make them more important without lots of fiddly bonuses. I don't like DR systems you'd see in GURPS or The Fantasy Trip, and more and more, I prefer avoiding subtracting modifiers entirely. Ignoring low results is quick and simple.
I thought about changing it to "ignore any damage roll of 1 or 2", but that might be too much. Plus, it gives the option of using that variant for shield walls or very large shields.
Part of the reasoning behind it is that I treat the damage roll as rating for the attack instead of a measure of physical destruction. Rolling a 1 means you're still doing a potentially deadly attack, but not the best you could do. Rolling a 6 means you've done the best attack possible with ordinary one-hand melee weapons, killing even the luckiest ordinary human.