I hope I am not misunderstood. I wasn't implying DRK can't. Only that I've felt a noticeable discrepancy. As to what it is I can't say.
I only ever cleared Odin via PLD using tank swaps (was a first day one-and-done clear, hadn't gone back since). So I don't know if it's different now with over-gearing allowing PLD solo tank (since I'm doing DF I didn't suggest solo tanking /w DRK to PUG, we swapped every 3 sannetales).
Mechanics > everything else. I alluded to this talking about the Ramuh PUG (we probably would have cleared if we had time for another attempt, got very close a few times). Every Vote Abandon coil/trial was due to one or more players refusing to abide mechanics, failing dodges, or any of the other typical experiences of Duty Finder. It was never a, "Bleh, a DRK. We lose," vibe.
But again there is a discrepancy I've felt. Whether it could be the passive EHP bonuses of a shield, a better familiarity with PLD, the additional micro required with DRK, or the utter gimp-ulation that happens when DRK blows their MP management.. who knows.
I like the extra micro of DRK, I like having control of our pseudo cool downs, 'cheating' their intended recast. But if it's a high risk == high reward paradigm, I'm not feeling the higher reward. (In fact my greatest appreciation for DRK at the moment comes from a glitch in a certain CD that will likely be patched soon)
No T13 for this plebian, but if PLD can handle it without any magic resistance up, I'd assume DRK can with just 15%. I've yet to feel the necessity of buffed Dark Mind except for a few occasions, and even then I don't think it amounted to much more than a once-in-a-trial relief for healers, or plain out getting over-healed.
Now if Dark Mind, when buffed with Dark Arts, granted +15% magic resistance up to self and all nearby party members, that I think is credible utility making DRK preferable. OT capable and great synergy with Delirium.