Experience versus focus, evening the odds

I've spoke before about the unevenness between classes, in particular the fact that some classes can kill players many levels higher.

It does make sense that a spell like lightning can cause full damage (or even extra damage) on a warrior equipped with full plate armour.

On the other hand it doesn't make much sense that a warrior almost 10 levels higher can be killed by a lower level mage. This is especially true at higher levels. Consider how much experience divides a level 81 mage and a level 89 warrior. The gulf of experience is enormous, extremely enormous. One must really consider the huge gulf of experience when looking at a show down between high level characters. Consider the number of wizards who attempted to stop Conan... and failed.

So the question is how do you bridge the gulf between a wizard's lightning and a high level warrior?

One answer is ... magic. It could be magical armour, or it could be something like a sword scabbard with magical protection properties.

What it shouldn't be is something that reduces the existing armour of a warrior. It shouldn't be an item in which a warrior needs to reduce his armour class to be immune to lightning. Perhaps it's something limited to warriors of a certain level, or something that requires enchantment by elves or a wizard.