Except it's not exactly fair to attribute the eHP gain to IB when it's clearly due to turning off Defiance.

IB is comparable to Rampart, that's what it was originally trying to mimic for war. So with rampart and IB it puts war in a really good spot (mainly because they don't have to use IB now). I'm not really of the opinion that they should take away abilities, and simply replacing rampart with shadow skin on drk doesn't put them in a better position except by knocking war down a peg. Drk needs another CD, whether it be a change to dark mind or something else. Bring DRK up to the level of PLD/WAR. All 3 tanks need to be relatively equal defensively. All 3 tanks need to provide relatively close raid utility. And all 3 tanks need to do relatively close damage. If one or more is skewed in favor of a particular tank then there will always be imbalance and they'll always be taken over the others.