I would like to share my thoughts about Dark Knight in Dawntrail based on the changes and how gameplay feels. I have played the job for 2 expansions for basically every single content I have done (Extremes, Savage, Ultimates, Criterion Savage) and my feedback is from testing and experiencing it post patch.

Dark Knnight does feel like it's missing something. I realized most of it has to do with the Delirium/Blood Weapon change and I will explain why plus feedback on other things:

-Combining both skills to reduce button bloat is fine (I'm not a fan but I understand why it happened and got used to it), however, it made MP worse.
-Blood Weapon only being 3 stacks as opposed to 5. This means 1200 less MP and 20 less Blood Gauge per minute. This not only nerfs the Dark Knight burst window since you lose an Edge of Shadow use every 2 minutes (2400 MP is enough to get another use considering the passive MP generation ticks and Syphon Strike uses), but it also will reduce the amount of Blackest Night uses, which is a nerf to defensive. It does feel really tight with the MP in specific, both for preparing burst windows and using defensively. This could be addressed in multiple ways as increasing Blood Weapon stacks back to 5 without increasing Delirium stacks or increasing the MP generated by Delirium moves. (Impalement already generates 500 per hit + 600 from Blood Weapon, but the actual single target combo is 200 per hit + 600 from Blood Weapon per attack.
-The new gap close Shadowstride is a very nice change in general, but it feels slower than Plunge in terms of activation and moving the character (half second delay) and it also doesn't generate enmity (which is already being addressed, this is mainly for dungeon scenarios). This also applies to Gunbreaker dash.
-Living Shadow lost one hit since Shadowstride doesn't do damage and Esteem always uses it no matter how close it is to the target.

I know most of it is just personal experience with the job and we got new skills and quality of life changes, but this is just things I noticed after playing it for a little bit in Dawntrail and it could improve the job more.