See, the problem I have with scenarios like this is that it speaks volumes more to your healers' skill than yours, or DRK/PLD's ability to mitigate damage in relation to one another, for that matter. And lets not pretend all of us were never "undergeared" whatever that means for this current level of progression. Strats change on a weekly basis, stuff people were doing two weeks ago with an eso weapon and maybe one other piece are bound to be inefficient now with 5+ pieces and possibly even 210 pieces. I just am baffled with strats like this where tanks actually go out of their way to mitigate as little damage as possible and dump it all on their healers' shoulders, and their healers let them. IMO its a huge flaw in raid design that this is even possible. And how is this "pushing performance"? Its lazy tanking. You're essentially a DPS that has aggro, and require almost as much effort to heal. Your healers may not cop to this, but it wouldn't shock me if that's all they've known.
On that note, have you ever actually tanked outside of Grit? Have you done it with a WAR OT? Obnoxious is not a strong enough word. You have to constantly babysit their enmity, and your aggro combo is your weakest DPS while their's is their strongest. Its not a huge deal, but yet another flaw in design that the game caters further to this kind of play for some jobs over the others. Everyone wants every tank to be WAR, stance dancing and dpsing and its straight-up not the same.
In regards to the actual debate in this thread, if you're going to factor in usage of Convalescence (which I didn't because while its a good CD, its not true mitigation b/c it requires intervention on your healer's part to be useful) for DRK you have to assume the PLD is doing the same (and getting more mileage out of it due to their trait). Delirium and Reprisal are awesome and a good DRK should try and have these up for a tank buster unless a big raidwide Gigaflare-type thing is coming, but if you're going to factor these in, you could just as easily factor in PLD's ability to Stoneskin and Clemency themselves before a big hit like this. What I'm actually saying is that PLD's mitigation isn't the lacking part, its their DPS, which, like BRD and MCN, is probably lower on the whole due to the fact that they have way more utility (WAR has Path/high MT/OT dps, DRK has Delirium/Reprisal, high mobility/AoE and MT dps... and PLD has Halone, Cover, Stoneskin, Clemency, Divine Veil, an emergency button that requires zero intervention on the part of anyone else in the party, etc.)
And I main DRK and I still realize that I can't support my party through my own mitigation and utilities like a PLD can. Obviously I still use these tools but I know my job's place in the spectrum. The biggest flaw in PLD right now is that you can't play the job effectively, taking advantage of everything it brings to the raid, in the current DPS fetishization that is the tanking metagame in FFXIV. Its a WAR's meta, the only reason DRK is getting any love is because A. its new and B. Dark Mind lets you LOL @ magic.