Indeed, so if WAR and DRK can actively manage specific debuffs that in effect give them similar DEF to PLD who has the passive DEF already, they can achieve the same defense that the PLD can. bu the same token, the far more tanky PLD can though their own skills with their damage dealing - as well as the potential impact on other damage dealt by healers for example, the end result could be a wash. but for a player who prefers the more active style of play PLD would be a nightmare because it would feel slower, where WAR and DRK would be so much more active that a player who prefers a more steady pace would enjoy PLD more.
To be honest I am not sure if you are wrong or not. I'm suggesting that all tanks could eventually achieve similar defensive resilience, but PLD can stand there and focus on other things, while WAR and DRK have to weave additional skills in to gain the same kind of defensive performance while tanking - passive vs pro-active defense. At the same time, if a WAR or DRK is using their proactive defense, it takes the edge of their damage dealing so that if they go full turtle with their pro-active defenses, it reduces their DPS to something more like the PLD can achieve.
So it becomes a balancing act. PLD has a harder time with meeting the DPS that WAR or DRK are capable of, but in order to achieve the same resilience of a PLD, both WAR and DRK end up doing less damage by burning GCDs on skills for that.
I haven't mathed this out,, it's nothing more than a concept. But it just seemed to me that an ability to actively balance offense and defense dynamically would fit WAR/DRK very well, while a PLD would be less dynamic through the passive defense. To balance this out, the Shield and Sword oaths could be used to create more variance between the stances so that the PLD can achieve decent DPS, with lower defenses - in effect the reverse of the WAR/DRK.
There's a really good chance that this is just a back of the envelope thought, I just like the idea of each tank filling specific niches better than other tanks. Also, During raid content (full party) passive party buffs could even things out to prevent PLD being *the* MT. But that would require even more balance at which my head starts to hurt.
I agree that each should have their reason to shine. I was just thinking that PLD making a virtue of their passive defense could be counterbalanced by active defensive skills that WAR/DRK could use.
Ah, well, it comes down to I play Paladin, and I would like there to be something that each tank is right for, and the party is therefore happy to see them - as you say.