The Current state of DRK

[CVXIV]

Dark knight is my favorite tank and it's a shame that it's in the state that it is.
When I first started playing the game I actually wanted to go dark knight but was unable to for obvious reasons, so I picked up paladin instead.
By the time I got to heavensward as a sprout it was the first thing I did, unlock that job and I really enjoyed it.
It's been one of the jobs I've always enjoyed in the franchise ever since I could be one in FFIII

One suggestion I would have is more in line with completely revamping it to resemble more what the job is based off of, a job that uses its own hp to deal major damage.
I know that's what the blood gauge is meant to represent, but I think having high risk/high reward would be a lot of fun, and it could have more self sustain to keep itself alive in a pinch
However I don't know if it would really work in an mmo setting, as cool as the idea sounds to me in my head

I think merging tbn and oblation would be a really good idea especially if the mp cost was either reduced or went away entirely
It could maybe be bumped up to 15% damage reduction on top of the shield, but maybe that'd be too strong
I mention the increase because other tanks like paladin and gunbreaker have around that for their 25 second cooldown, on top of the other bonuses they provide

[Zimmerson]

One suggestion I would have is more in line with completely revamping it to resemble more what the job is based off of, a job that uses its own hp to deal major damage.
I know that's what the blood gauge is meant to represent, but I think having high risk/high reward would be a lot of fun, and it could have more self sustain to keep itself alive in a pinch
However I don't know if it would really work in an mmo setting, as cool as the idea sounds to me in my head

As much as it would be cool to use ones own health to deal DPS, I don't believe it would be a good idea in PVE. For example, BLM back in the day had an ability called "Convert" that allowed to converted 20% of your HP into MP. This often ended up with BLMs dying to raidwides due to the lack of HP.
If this was a thing for DRK - it would make main tanking for DRK difficult, or force it into an off-tank role. I love playing MT so it'd basically be unviable for me to use this to it's full potential due to being hit by auto's and mechanics, which can pack a punch. You could argue that - "Just mit more", but you'd end up burning through your mitigations that you would want to save for something like M3S's 6 back-to-back Tankbuster hits.

This change would also force the healers to watch your HP more and have to be more proactive in keeping you alive, lest the DRK dies. Last thing you need is for a DRK to be greeding for extra damage before being given a bloody nose by the boss/enemy before murdering either the DPS/Healers or the co-tank that didn't mit for a tankbuster as they weren't expecting you to die.