I would say there are a few pain points.

1) Blood Price is bollocks and is completely useless outside of generating blood gauge. its MP restoration has been nerfed to the ground unless you are getting hit by an entire dungeon.

2) Dark Mind is near pointless. It no longer servers the unique purpose it had in 3.0, which helped separate DRK and PLD. Now its just kind of a gimp cool down. Imo Dark mind should just have its magic damage reduction changed to a general damage reduction while keeping everything else the same.

3) Dark Passenger is now completely useless.

4)No Scourge

5) Delirium needs a recast reduction.

6) We lost a lot of our moves and gain virtually nothing. Reprisal : Taken and Nerfed, Dark dance: Taken, Scourge: removed, Shadowskin: removed, Dark Passenger: nerfed into uselessness. In terms of sheer job abilities DRK got royally screwed.

7) My biggest gripe is all the complexity has been removed from the job. DRK used to be loaded with off GCD's to manage as well as 3 combos with MP management. Now it just uncomplicated as 3.0 PLD with none of the advantages. Basically 3.0 PLD and 3.0 DRK switched places and styles in 4.0. Instead of just buffing PLD they basically took what was great about DRK and gave it to PLD