Good points. I don't think your loss to the epic encounter is the proof you think it is, but the other points are pretty strong for suggesting a problem. I always assumed that defense was mitigation, but that is the berserker mentality in me. I wonder if you tried the same thing on say a monk if you would get the same results as they are considered the avoidance tanks. Maybe there is a cap on the defense stat now or a bug there or something completely different. There are a number of things that need to be looked at in that if what you say is repeatable.