The only people I see/hear that are having issues with DRK are the ones that aren't tanking material to begin with.
I'm not here to point out all the good things a DRK brings to the table, because frankly I don't think those bashing DRK would either care nor understand what I would say.
I AM here to make the point that 2.0 war had some issues back when ARR released. These issues were truly game breaking and made the class nigh unplayable. DRK is in a similar boat, but no where near as bad. We could use a slight buffer here and there, sure, but most jobs can right now tbh.
I see plenty of DRKs clearing Savage Alexander and I hear very very few of them complain about DRK being underwhelming, not viable in end game raids, or even that DRK needs major buffs. The fact is, they practiced and mastered DRK.
My advice to you would be to stop using jobs you simply don't like, and go play a job that you do like.
(Also, rose-tinted glasses were off at the time of this posting).