I think this is being made a bigger deal because of how it sounds on paper. In my experience, I've probably failed at least as many times as I've succeeded in saving myself with Defiance/Equilibrium. Grade A example last night: I'm sitting at 15-20k HP just taking autos from Kefka. With regen ticks here I float. AA down to 3k HP. ToB/Conv down for another 15 sec. Will I get a heal? I guess I'll have to go to Defiance and Eq. Alright here's Defi... Oh I'm dead
That's obviously on me for delaying (and my healers for making me wonder), but my point is that it's no guarantee Warrior's Super Awesome Tanking Kit™ is always gonna save your hide. Certainly if you can plan for it's usage at a given point it's easier to prepare for and very smooth to execute, but just on the fly like that more decisions have to made and it doesn't always work out. And that kind of situation has happened more times than I care to even keep track of, but maybe it's just me lol. It is nice when it works, no doubt about that
As it relates to PLD/DRK, if in the same situation it seems like all you'd really need to do is glance at your MP and decide if you have enough to execute a Clem/TBN on yourself. In a pinch you'd probably just start mashing the button and it either would or wouldn't activate. You don't need to equip a tank stance or try to figure how to weave swapping to tank stance during your GCD so you don't lose one. It's just a simple one push heal/shield button. Maybe that's simplifying it a bit, but really it's no more than Def/Eq is being simplified.
I'm not sure how you got to this conclusion. Does that mean you're going to stop using Sheltron/TBN? If content required more frequent on-demand mitigation, War is more than capable of providing it. But since it's locked behind tank stance it would likely just move to back to the OT role to optimize it's damage instead. And, since you're using Sheltron/TBN despite content not requiring it, do you not think War would use IB more if were unlocked from Defiance?
I hate to say this, but they probably should have unlocked IB from Defiance instead of giving War Rampart.