Just because a job design works well for a given expansion doesn't mean that it would work well in a different expansion.
Heavensward DRK worked well for 3.x. That's not because it was the best designed job. It just worked well for its time. It wasn't without flaws. If you used Dark Arts with Dark Dance, for example, you'd boost your evasion. But DRK relied on getting hit (especially by autos) in order to get Blood Price ticks, as well as to get parries to trigger Low Blow resets and Reprisal procs. There were many parts of the design that just clashed with each other. In addition, a lot of players at the time either didn't realize that spending MP on defensive Dark Arts buffs cost DPS to use, or didn't mind doing so. Some of the job's highlights, such as being the only tank with a gap closer, are things that we are less excited by now because it's a standard across all jobs. And I think most importantly, players were willing to overlook a lot of faults because it was a relatively high DPS job which was also viewed as relatively high skill to play.
Stormblood DRK did not work well for 4.x. It was a relatively low DPS job which was viewed widely as relatively low skill to play. It also unearthed a lot of the underlying weaknesses in Heavensward's design, because players were starting to realize that Dark Arts = Potency, and weren't willing to use a lot of their kit because they were gated behind DPS losses. If you look at the 4.3 changes, a lot of them just added the 140/168 potency as standard to every time you pressed the Dark Arts button. It's actually not rocket science to see why Edge/Flood replaced it. I have a really hard time taking people seriously when they claim to have loved Stormblood DRK back in the day, because a lot of those exact same posters were campaigning to get the job changed during 4.x.
I think that if you took either of these jobs and just copied them into the current expansion, players would be extremely unhappy. The game has changed. All the other jobs have changed, and no job exists in a vacuum. So you can't silence discourse on the job. It has to evolve with the game.
Regardless of whether you like the aesthetic choices made, it's hard not to see Shadowbringers DRK as a more streamlined, synergistic version of the job compared to previous iterations. I suspect you'd see a lot less complaints if it wasn't a lower dps tank for the second expansion running. Would I like to see a speed buff again? Yes. But maybe the solution is to do something situational like Reaper does, dropping to a 1.5 s GCD in Avatar form. Would I like to see a different aesthetic on Delirium? Probably, but every tank has a one button spam window now, especially with GNB's combo being turned into a single button. And I absolutely, definitely don't want to go back to Stormblood's Delirium, which was the most awkward, most ineffectual 'burst' window of all time. You do not burst by increasing the duration on something. You burst by increasing the potency. Whoever designed that was delirious. I'd sooner lose Delirium over Salted Earth, if they ever reverted that change. Players across all language forums wanted to burn it with fire during Stormblood.
Do I want to see Living Dead changed? Definitely. And I want the dev team to actually talk about invulns and the impact that they've had on fight design to date, rather than avoiding the topic. I actually want to see invulns removed and an emphasis placed on learning how much to actually mitigate.
This is not a generational thing. The game changes, and the jobs have to change with it. I think if Warcraft classic proved anything, as much as players think they want to go back to earlier points in time in an MMO's history, they actually don't. Keep your memories of Heavensward and Stormblood. But you'll think more fondly of them if you let them stay in the past.