To answer the question: Yes. Very much so. Its actually a potency gain after three GCDs to AoE two targets via unleash/soul on top of faster MP and blood generation leading to more spills and flood. Of all the tanks, DRK gains the most from AoEing two targets. I didn't believe it but its very much true. The only tank that should not be AoEing is PLD except for during Requiscat where they holy circle over spirit.