User blog comment:Atmey/Impregnable Mail/@comment-5287086-20130107224512

If you're getting burst down through your resistances, it's time to stack health. It's not time to invent a new stat(your penetration resistance thing) that counters a stat(penetration) that counters a stat(resistances) that counters a stat(AD/AP). It's just redundant, and you've already got plenty to fall back on.