As someone who for the most part liked the changes for DRK in Shadowbringer, minus some issues with some stuff that I feel should have been addressed such as Living Dead; I find the changes, or lack thereof, for DRK in Endwalker to be a combination of underwhelming and downright disappointing.
One of the reasons that I actually was okay with the Shadowbringer rework was that I felt it established a more solid foundation to build off of and actually try to create some interesting game-play elements from.
Unfortunately this opportunity was completely missed and instead just a few things were added, none of which expand upon or evolve any of DRK's game-play. It really is just a bit more of the same and a very measly bit at that.
The capstone lvl.90 ability, Shadowbringer, is imo a huge letdown in that it brings very little to the table in terms of game-play. Yes we, or at minimum I, wanted more oGCD usage on DRK but a single extra oGCD every 60s is virtually nothing in terms of evolving DRK's game-play in any direction, let alone emphasizing a game-play style that relies more on oGCDs as opposed to strict GCD rotations more akin to the other tanks.
I honestly feel that the guessed implementation that the community had where the ability was actually a GCD ability that was procced off of using Edge/Flood would have been way more interesting, sort of like a reverse Continuation where an oGCD procced a GCD, and would have gone a great way to diversifying DRK game-play and helping to establish a more unique feel to the way the job plays. The actual implementation is immensely boring in that it has zero interaction and doesn't play off of any of DRK's other abilities or aspects in any meaningful way.
I also find Oblation very disappointing. Sure, it is another defensive ability that can be used on yourself or an ally, which in a vacuum is great. However, when looked at in the context of the niche in which the ability is filling and comparing that to the updates that the other tanks jobs got to fill said niche, Oblation falls short. The other jobs have all had their primary self-defense and support ability buffed so they now all include a base-line aspect of mitigation with a longer duration, additional stacking mitigation on a short duration and self/target-healing. Oblation basically only really equates to the stacking extra mitigation aspect, leaving DRK short on the healing part, something that DRK is already severely lacking compared to the other tanks. On top of that Oblation is on a 60s cooldown while the other tanks get to take advantage of their defensive buffs far more frequently at approximately every 30s since those are layered onto their frequent use defensive/support abilities. Oblation having 2 charges doesn't compensate for being able to use it at half the frequency of it's equivalents on the other tanks. Then there is the quality-of-life/ease-of-use consideration where Oblation being it's own ability requires you to do two separate actions when you want to stack it with TBN for a tank-buster which is an annoyance when you have to do it to yourself and incredibly so if you are wanting to do that on another player. To be fair though, there is a silver-lining to them being separate in that you could separate their usages to cover different periods of incoming damage when the other tanks can't. However, I don't feel that this one potential benefit outweighs the multiple drawbacks of this ability compared to the others.
Enhanced Unmend ... well, there isn't really much to say about this asides from it seeming like a complete waste of a trait. It feels like it was just shoehorned in there so that there would be something to fill up that spot while also being like "look, see there is ability interaction in the DRK kit now!" while adding such interaction to probably the least used ability in the kit, Unmend. Who knows, maybe the fight designs will require a lot more disengaging and usage of the tank range attacks and this trait will actually be useful, but I definitely have my doubts. Interactions between abilities like this should be tied to abilities and game-play aspects that are more central to a job's kit, like Enhanced Infuriate on WAR. Two core abilities interacting with each other, that is good. Two fairly tangential abilities not central to the kit interacting with each other, why even bother?
Two separate "Enhanced Living Shadow" traits just two levels apart? Another absolute waste of a trait.
I will say though that I actually do somewhat like Salt and Darkness in that it provides a new ability that actually plays off of another ability, Salted Earth. That is a welcome change on DRK and I for one would like to see more game-play and ability tie-ins like that.
Then there are all the issues that have been consistently repeated for years now that have not been addressed. The death penalty on Living Dead needs to be addressed. The duration and/or not going the route of stacks for Blood Weapon needs to be addressed. The lack of good self-healing outside of mass dungeon pulls when compared to the other tanks, especially now, needs to be addressed.
And those are only my big issues, not even including the often repeated complaints of there needing to be more to Delirium than just spamming a singular button 5, or now 3, times. I think this complaint is extra warranted now since all the other jobs have had more complexity added to their spam burst game-play. Even WAR got a Confiteor-like ability to mix up their Inner Release spam.
Overall I feel that the Endwalker DRK is a huge missed opportunity to grow and do something fun with Dark Knight and they made some glaringly obvious mistakes with what they added to this job compared to the others in terms of complexity and as it also appears, to just basic balance. Too much of the changes just feel like uninspired filler.
Basically it is like I have been saying for a while after Shadowbringer release, it feels like DRK is one expansion behind the other tanks in terms of their kit. The Endwalker version of DRK fits better for what DRK should have been for Shadowbringer and now with Endwalker it seems like all the other tanks evolved along similar lines to fit the new expansion and DRK is still one expansion behind, only evolving enough to match where the tanks were with the previous expansion.