You could always bring into play the scale of the weapon being used vs. that of the armour value and the stamina/endurance/might aspects of the target. This has been brought up in earlier discussions of Fudge and Fate 2.0

The idea is this: (Extreme example) Even if you have an armour value of, let's say 10, then a weapon:6 would not stand a chance to penetrate and do any damage if you were just using a straight game mechanic (Assuming a Great (+4) hit result. so max damage would be Legendary + 2= 10). However, throw in the fact that a w:6 has a lot of "ooommmph" going for it, the force is still gonna knock your butt on the ground. Kinetic/concussive force is still force. That kind of result would at least give out some free tags to the baddies for maneuvers or something.

Though hypothetical (at least as far as I know . . .) this could apply to the magic realm as well.
Your intrepid wizard might be able to evoke a Superb (+5) level shield to entirely block a w:4 attack that got rolled at a "zero" for effect, you could still reasonably say that that the force of the attack was strong enough to do something. What that would be would depend on the defenders might or some other physical attribute.

It all really depends on how "crunchy" you want to get. The golden rule is the play is more important than the mechanic.