While this might not be the same thing, DEX over VIT, at least for a paladin, seems to be like taking crit over det on a whm. While the crit may indeed help from time to time, you're betting on a gamble, but you may not have found yourself needing that crit had your thoroughput just been higher overall. Similarly, while higher DEX reduces the damage you take from time to time, every OTHER unmitigated blow strikes you for a larger percentage of your total health. This makes it harder for your healer to get a read on your rate of death, and kind of flies in the face of the mechanics paladin was built around.