Now before anyone says "Dark Knight is fine" or "it doesn't need another rework", etc, listen up.
Dark Knight IS fine. But it's the most boring, stale, straightforward job in the game now.
Yes, it gets the job done, but I don't just play a game (especially an MMO) to reach some end goal. If I wanted to do that, I'd just stick to working a 9-5 job, slowly losing my sanity. I play games to have a thing called fun. Because games are supposed to be fun... right?
The entire idea of Dark Knight in Stormblood was amazing. I don't care if you didn't like spamming Dark Arts, there was an equal amount of people who LIKED that mechanic, and honestly it was the only thing setting DRK apart from the other tanks. While I understand that it wasn't working for Savage progression raiders, not everyone in the game is at that level. At the same time, people who pick up a job and play it for a couple hours and don't like it shouldn't affect how a job is changed either. The middleman DRK mains are then screwed over by a handful of personal, narrow, & skewed opinions and a massive amount of inexperienced opinions. And while yes, I get it, Square primarily uses data rather than direct player opinions, data doesn't complain. So don't even try to bring that up.
At this point I have 175+ days and some hours in play time. And while there's no definitive way to find this, I think it's safe to say I spent around 30-40 of those days in total play time on Dark Knight, hence it being the second job I maxed. Not only that, I cleared my 1000 instance run achievement primarily on DRK (not all of those runs would have gone towards the Tank You achievement btw), so I think I have some reasonable grounds to judge this job on its current, sorry state.
Sustain
Dark Knight was the absolute KING of sustain next to Paladin being a borderline healer thanks to Clemency. Sure, Warrior has their self heal, but Dark Knight was healing constantly. While yes, I can understand where that would be a bit unbalanced, but at the same time I can look over and see Paladin soloing Shadowbringers dungeon bosses down from ~30% with their massive heal. With the loss of damage % based healing on Souleater and Abyssal Drain, DRK has now been future proofed to just always be bad at self sustain. I used to be able to get 25% of my health back with a direct critical, DA Souleater and now I struggle to even heal back half of a boss' auto attack. I don't think I need to explain why Abyssal Drain is bad now, you can probably look up 'joke' in the dictionary and you'd see the icon and tooltip for it.