Here's a hot take. Channeling Tank Roles for a second sorry
DRK has never been actually well designed in FFXIV. In every single iteration of the job, it has had some jank mechanic, some poorly designed mistake, something that handicaps it. HW DRK was a fantastic base of a job, that really shouldn't have changed too much. But don't say that it's because PLDs were complaining, it was because they deliberately designed a raid series with DRK in mind, primarily through heavy hitting magic attacks. You wanted NIN and DRG, so there was no spot for MNK for magic down via Dragon Kick, so of course, PLD with Phys down versus DRK with Magic down was rejected. Who cares about phys down when everything in the game had Mega Holy or something. It didn't help that you couldn't BLOCK MAGIC for some asinine reason. While at the same time making WAR mandatory, an actual powerhouse. Someone had to be last. No one ever used DA for anything but offensives honestly, because there was rarely a reason to use things like DADM, or DADD, especially in Creator. Same mentality that removed pre-ShB tanks stances, they were effectively dead buttons, and the only exception was DADP. And even DADP is a perfect example of why HW DRK is so odd, since things had to hit you with Blood Price for MP regen, you needed parries for Low Blow and Reprisal, but DADP made them miss with blind debuffs? Why?
Instead of fixing these things, they gutted HW DRK to make SB DRK. Deleting great and interesting actions to homogenize them into the role action system, or deleting them outright. Removing the Darkside drain was a mistake so grave, it's on par with the SCH's Energy Drain removals. Except we never got it back. Of course SB DRK was going to devolve into DA spam, SE didn't replace the MP drain with anything, so players are going to start using the ONLY recourse left, using as much DA as possible, like we did back in HW. Except now, there's no Scourge management, there's no Delirium management, there's again, very little reason to use aggro combos, AND DP is a DPS loss in single target in comps without a SMN. Then they add in a new delirium that skyrockets MP gain even faster, on top of reducing it's cooldown in 4.3. Of course it's going to devolve into "SHINY BUTTON MUST PRESS RIGHT NOW". The only positive thing about SB DRK, is that Blood Weapon remained really good as an offensive action, and there was significantly more interplay between Blood, MP, and your damage output. Abyssal was STILL a GCD, and it STILL required MP, but since they added Bloodspiller/Quietus/TBN, the kit interactivity was on an unprecedented level. MP could give blood, blood could give MP, it was all a cycle on DRK. There was still an MP economy, just in the opposite direction, draining vs overcapping, to make the job less punishing. I have always said that much like the HW environment denied PLD players the opportunities they wanted, SB denied DRK players a legitimate reason to play the job in a practical fashion outside of TBN, particularly if you were a player who was more fond of HW DRK. There was simply no need for DRK to exist with no raid-mitigation, a high skill floor, and being rejected by a large portion of the playerbase. DRK had an identity in SB. Speed, TBN, stockpiling, and I guess, being the underdog, you really had to prove you and DRK weren't trash. It was contentious, it was not popular with people who didn't dedicate themselves to DRK at any cost, but it was there. Stupid decisions all around though.
Then what does Shadowbringers do? Delete everything again. Now because people can't resist pressing shiny button, and just waiting for raid buffs, we're going to gut anything positive about SB DRK to make ShB DRK. Look at Salted Earth. Look at jank, broken Blood Weapon. Those skills are completely gutted like how they gutted Reprisal in SB. Like how Dark Arts now is a poor man's replacement for Low Blow procs and "kit synergy". When your level 80 level rotation looks like THIS.
Look at all of those double weaves in the opener! That's a lot of ( not dark arts) spam. Then nothing. 123ing yourself into grave. You are TBN bot with overlong 60 sec cooldowns in ShB, at the best of times. If you don't have a team that allows you to utilize the admittedly very fun, and very interesting 5/3 or 6/2 edge rotations in burst, you have a less engaging and diverse GCD, and oGCD experience than a level 26 Rogue 3/4ths of the time (this is almost hyperbole, don't take it too seriously). The best thing ShB DRK did was remove the insanity of SB Dark Arts by simply INCREASING the MP costs and potency of MP spenders, which on it's own could've fixed that trainwreck. That came at the cost of Darkside becoming a non-mechanic you can't drop, the speed, the cost of actions being affected by each other, and the entire MP > Blood resource economy. I can't even augment my skills anymore? DRK has an identity now, and it's called, "TBN good and Living Dead bad". No one ever talks about how it's actually one of the highest raid buff abusers in the entire game, something that it shares with SB DRK, because that's not interesting enough for people. It's just easy to get into now because the skill floor is in the basement.
There has never been a good, balanced, well-designed version of DRK. Just revisionist history about how bad or good or braindead or gigabrain it is/used to be, here's how I would change it (your post has exceeded the character limit, please shorten the post) The true identity of a DRK is constantly in flux because of SE's development, some side of it's playerbase is always going to be disappointed with it, no matter what. It's been changed too many times. But TBN is good so I guess that keeps it relevant. What an absolute mess it has been over the years.
Either the raid environment around it was warped due to or in spite of it's presence, or the job itself was self-sabotaging. ShB DRK is so milquetoast though, that EW DRK might be pretty cool, I think. Being a DRK main is whack man. I like watching Asmongold play it though, I like seeing people have fun.