During my earlier "easy" run, I remember the Rogue constantly ran to the Confessor to kick her. My Death Knight also has a "interrupt focus target" macro, but it requires whatever I'm hitting to be close to the Confessor, which is rarely the case in PUGs.
I do admit, I wasn't been the best healer during this last run. I didn't hug on the third phase of The Black Knight, but mostly because I had a ghoul humping my leg so I had to spam Nourish to keep anyone up. It's sad when you can't switch away from Nourish spam to cast HoTs because people die in the global cooldown. Especially since Nourish spam rarely works. Someone gets marked and one Nourish isn't enough to heal through that, but you can't apply Rejuvenation and Regrowth because everyone else will die in the global cooldowns.
It's ridiculous.