My take on 5.0 DRK changes

[Dtrip19]

My list of what I believe are reasonable and elegant changes/additions to DRK to reduce clunk and increase decision making.

Stance Changes: DRK's stances now function similarly to WAR's, with the one exception being that DRK's stances would cost 600 MP at lvl 70 to switch. Grit Increases Enmity Generated, enhances regenerative effects of Souleater, Syphon Strike, Blood Weapon, Blood Price. No longer reduces damage dealt or taken.
Darkside No changes

Action Changes:
Blood Weapon and Blood Price. Blood weapon would now be unlocked in Grit, while also draining HP as well as MP while in Grit. Blood Price would have its wording changed to: "Restores MP equal to a portion of damage taken". In Darkside, 10% of damage taken would be converted to MP, in Grit, 15% would be restored. This will make the ability useful in any situation where you are taking heavy damage, regardless of how many individual times you take damage. Additionally, on use of Blood Weapon or Blood Price, the action would change to "Delirium: Blood Weapon" or "Delirium: Blood Price" respectively, so you couldn't use both blood abilities then use delirium to extend them both.

Sole Survivor. "Deals damage with a potency of X over time, restoring HP and MP equal to the damage dealt. Duration: 21 seconds. If the target would die before Sole Survivor ends, twice the HP and MP that would have been restored over the remaining duration is restored instead. Duration is extended by 6 seconds when target is hit by Bloodspiller. Recast time: 60 seconds". The potency should be adjusted so that it deals damage equal to around 10% of the DRK's max HP

Salted Earth, which will now give DRK party damage mitigation. Upon use of Salted Earth, the action will be replaced by "Dark Barrier". Casting Dark Barrier converts the Salted Earth circle into a dome of darkness that reduces the damage taken of all party members who stand inside by 15%. The duration of Dark Barrier will be 10 seconds, or the remaining duration of Salted Earth, whichever amount is lower. You can't extend the effect of your Salted Earth by converting it at the last second, but you also can't have a 15% damage mitigation sitting up for 20 seconds if you instantly convert Salted Earth.

Dark Arts Dark Arts is now a toggled ability that automatically consumes MP upon using a previously listed ability to enhance its damage and effects. Healing from Souleater is now tied to Dark Arts. 50% of damage dealt is restored in Darkside, 100% in Grit.

Miscellaneous Changes
Dark Passenger Hitbox shape is now a cone, MP cost reduced to that of Abyssal Drain
Blood Guage Max blood stored increased to 120, allowing DRK to store a little excess blood than it needs for 2 abilities, similar to how NIN's Ninki Guage goes up to 100 despite their Ninki abilities only costing 80.

[Rollout]

Blood weapon would now be unlocked in Grit, while also draining HP as well as MP while in Grit.

No. Not going to happen. Never, ever, ever, ever going to happen.
They will not design a tank in FFXIV that will sacrifice its health to do something.
If they made Dark Knight a DPS, then maybe, but they won't design a tank that reduces it's own health on purpose.

[Dtrip19]

I meant draining as in taking from the enemy, like how blood weapon is supposed to "drain" mp from the enemy for the DRK

[Agner]

Might wanna edit that to the term lifesteal to avoid any further confusion then, as that would be what most people recognize it as. :P

[Kabooa]

What a click bait title. I thought they did a sneak peek.