I agree, warrior's cooldown kit is likely the way it is becuase their tank stance benefit is only active when they have full health. So they have the benefit of having a high uptime on mitigation. If we do as SE assumes and keep high uptime on tank stance, then maybe the tanks are sorta balanced in terms of mitigation.
However, lets suppose for a minute that the people who play the game have found a way to play the game which doesn't use 100% uptime on tank stance. Well then what you've done is you've created one job that fits this meta super well and two jobs that can get by in a similar fasion. What SE wants and how to optimize tank play are two different things. The faster SE stops trying to force roles into playing the way they want and assuming this is how we will play the faster things can get balanced.
In general, I'm saving my thoughts on the fixes for tomorrow so I can see patch notes especially given SE's history of keeping information close to the chest.
My opinion on fixes is this, the jobs people are most excited for, paladin, bard, samurai and so on, they have a clear identity that feels like their kit just fits into naturally with their lore. When it comes to dark knight, I feel more and more of this identity and lore gets patched away as we become paladins without shields.
Gone is the mentality of "You can hit me, but its gonna hurt", reprisal: parry the attack damage the enemy and lower their damage, low blow procs: hit me so I can parry and reset my low blow, blood price: hit me and refill a chunk of my mana so I can use it against you (I guess this still works if you get hit 20 times? I'm counting it as not there). Gone is the idea that we are constantly draining ourselves to output damage. Gone are the days of debuffing the boss to take less damage (3.x delirium). For now, we still have selfsustain in the form of lifesteal and some resource steal, I guess that makes us dark knights, for now.