When Yoshi was asked about possibly adding more meaningful DPS kits to healers his reply was basically "LOL just play SGE, wtf?" So when the time comes to address the DRK issues in dungeons don't be surprised if SE answers with "Well uh, certain tanks are a better choice for certain content..." In Yoshi's defense DRK in 8mn content is very fun to play, but during trash pulls not so much. Honestly the quickest fixes they could do for DRK in short term is maybe something like changing Abyssal Drain into a WS that would be 3rd step of our aoe combo that still retains the healing element (nerfed slightly) and of course redesigning Living Dead.

Disclaimer, I myself have no issue healing DRKs but when I play DRK myself I dislike the over reliance on the healer during trash. The stark difference between DRK and WAR in dungeons needs to be addressed. You could argue that DRK is the expert mode of tanks because you have zero safety nets unlike PLD that cannot die in dungeons but still DRK's kit seems jank as hell in dungeon pulls unlike the very synergistic kits of WAR and PLD.

Sigh, I miss stormblood DRK...