I actually prefer that Delirium has no DA effect, because then I can pre-cast DA in preparation for an enhanced defensive, AD, or DP. Having Delirium consume it would actually make the rotation feel far more clunky to me, and the DRK generally less fluid or responsive.

Pipedream-wise, I'd love to retool all three finishers slightly to bring out a more bastardly, dastardly, terrifyingly badass DRK identity, but for now they all seem just fine. I'd just like for Delirium to be able to be present at the same time as Dragon Kick without actually stacking the Int Down effect. It can be annoying when a raid hit goes off that, had the debuff not been removed by DK, Delirium would have been up for. It would also aid any small buffs it might eventually receive.

If we're still worried about the near-guaranteed WAR slot after that, could always add a tiny something to RoH and Delirium. RoH, for instance, could reduce Evasion, aiding low-accuracy healer damage or being rotateable to allow melee DPS to drop some accuracy in favor of offensive secondary stats, while Delirium reduces hit chance very slightly, somewhat decreasing damage taken over time. In that way, they're each potentially a bit more worthwhile on pure-physical or pure-magical enemies respectively than Path would be. The best option, of course, would be that they each have some, less obvious, usage on the opposite type, as to compete with Path's dual-type effect, but I've no ideas for that yet.

The only thing I feel like DRK really needs is a way, even if costly, to activate Reprisal from the OT position. There can be swap timings where, no matter who starts, Reprisal may be unavailable when needed. Sole Survivor allowing parry proc sharing while diverting or sharing some portion of your parry chance to/with an allied target is my preferred method. Attach whatever other secondary effects you like, and now you have a interesting, even if inferior, Cover alternative that allows OT Reprisal usage. Oh, and a 30 to 70% reduction to Grit MP cost or some secondary effect added to its cast to warrant both nearly a DA of MP being spent and a whole GCD...