Combat system is beyond saving.

[Enjuden]

I was more referring to the limits you could push in non-raid content (like dungeons) where there was endless fun to be had in trying to maximize the damage you could deal while also staying just on the edge of losing aggro or dying because you lost the damage reduction from tank stance. If all you wanted to do was hold aggro and not worry about anything else you could just turn on stance and walk forward while you spammed flash and used DCDs which is basically how every tank has been forced to play for many years now. There is no depth, no reward, no excitement. The dungeons mobs can't kill you, you can't lose aggro, and everyone does pretty much the exact same DPS assuming you have the same gear on while we mash the same 3 abilities without thinking for 17 minutes in a dungeon.

People really have this strange idea that Heavensward magically was able to kill you in non-raid content when it was exactly the same every expansion. Only one dungeon did that and it was release Vault, and that was because AST/MCH was horrendously bad on launch and took a long time for them to fix. And frankly, was overtuned comparatively to the rest of the dungeons in that expansion. Only one raid did that, and it was Mhach, and that was Ozma being Ozma.

You couldn't die or lose aggro regardless unless you were not pushing your mitigation or you decided to pull wall to wall while the rest of the party refuses to aoe for whatever reason. Difficulty in dungeons specifically was and always is because of terrible players being terrible. The same players will refuse to do things out of sheer spite instead of playing the game as it was made.

The rest of your points are baseless at best and hyperbolic at worst, and is a complete waste of time going into, with the only exception being job design being poor. Job design was bad then too, and worse than now. DRK being the only exception to that rule.