Bardam's Mettle is pretty gear gated dungeon. Poetics gear shows it weakness in that dungeon on every tank. When I levelled up my tanks through that range, I made a fully crafted set of lv66 gear set. I would routinely hit 66 in middle of a run and my survivability increased leaps and bounds as soon I crossed the threshold and put on the new gear.
But saying that, the WHMs you had in bad runs were too interested in casting Holy than giving you proper regeneration and attention.

You can also use both Arm's Length and Reprisal; as those are great defensive CDs too. Arm's Length is only good against trashpacks but that is what dungeons are full of.