Oh, I agree. I've been saying since Heavensward released that DRK was half-baked and really needed more utility, offensive utility at that to compete with Paladin. Little did I know that Paladin was going to get absolutely bodied by Gordias, beaten to a pulp by Midas, and smacked across the face by the Creator. But, that changes little now. Now, we're dealing with an even weaker DRK (offensively at least) and have gained only one support ability to make up for the loss of Reprisal's longer duration and Delirium. If I could `just wave a wand and change it, I'd do the following:
I'd add back in Scourge (225 and then 375 over 15s) which combos off of Syphon Strike now and can be enhanced to raise the party's skill and spell speed by 5% for the same duration (15s).
I'd leave Syphon Strike as is.
I'd make Bloodspiller more potent (520, still ignores Grit's debuff) and remove the DA part.
I'd leave Dark Passenger as it was.
I'd leave Darkside as it was.
I'd add in Shadow Spikes instead of Quietus. Shadow Spikes, like Radiant Shield and Vengeance, reflects damage (35, 15s duration), with the added effect of gradually raising the target's vulnerability (2% per stack, stacks to 5 times, 4s duration).