I would like to start this by saying that I like the design and feel of 5.0 DRK. Ever since I picked up DRK as my first tank job since starting this game, I have grown to really enjoy the flow of the job.
I have read the many, many complaints about the job. Most of these haven't really concerned me. Living Dead can be frustrating, I agree, but when I'm paired with the healers in my static, we never have an issue.
There is one subject that I would like to discuss here, which is self-healing. Out of all the tanks, DRK lacks in the area of self-healing. Abyssal Drain, while fantastic for double pulls in dungeons, is completely useless during a single-target boss fight, and depending on crits, will do less healing than my regular 1-2-3 combo. However, while I want DRK to receive a self-heal ability, I would prefer it match DRK's identity. Each of the other tank's have a healing ability which matches their identity: WAR enjoying the thrill of battle and nascent flash, PLD casting self healing spells, and GNB having essentially a field medicine kit on hand through Aurora.
Here is my idea for a DRK self-heal:

1) Remove "Living Shadow" from the Blood Gauge and place it on a 2 minute cooldown. If a condition must be met, let it be under the effect of "dark side"

2) In place of "Living Shadow," add an off-global self-heal ability to blood gauge. This can cost 50 blood gauge as the other abilities do, and for a bonus, it can be named "Blood Price," the lv. 35 DRK ability from Heavensward. This change accomplishes two things:
DRK is unique in that it uses two different gauges in its rotation: MP and Blood Gauge. Of the MP abilities, DRK has a single target attack (Edge of Shadow), an AoE attack (Flood of Shadow), and a mitigation (The Blackest Night). On the Blood Gauge side, we have a single target attack (Bloodspiller), an AoE attack (Quietus), but no mitigation. As a result, "Living Shadow" feels out of place on the Blood Gauge because it doesn't match the pattern set by MP.
By placing a self-heal ability tied that uses 50 Blood Gauge, this makes DRK require more strategy in a fight. A single use of "Blood Weapon" can charge at least one use of Blood Gauge for emergencies. Otherwise, this adds an extra dimension to Savage fight planning. A DRK can charge a full Blood Gauge in advance for intense healing mechanics, or for use during Walking Dead to help healers with resolving the "Walking Dead" debuff. So I as a DRK have an extra thing to think about: do I want to use my Blood Gauge for DPS or for self-healing? It makes DRK more flexible in both dungeon and boss fights.
I think the above changes will satisfy some dissatisfactions in the community. Personally, I will continue to main DRK into 6.0 and Savage Prog, and I'm looking forward to the Delirium changes giving a DRK a more active rotation which is in sync with all its off-globals. Thank you!