So what is PLD good at?

[Cabalabob]

Snip

You failed to consider tank stances. PLD with convalesce up has -20% damage taken and +30% healing recieved. That's stronger than a WAR with IB and defiance on which is 20% damage taken and 25% healing recieved.

Vengeance + IB is stronger than sentinel yes, but not stronger than sentinel when you also factor in shield oath putting it at about 55% damage taken. And the possibility of a block taking it down by another 30%.

As for bulwark, you should not be using that alone as mitigation for tank busters and should never need to, with a couple exceptions. Bulwark is something to use to mitigate auto attack damage and proc shield swipes, having almost every auto attack leading up to and after a tank buster can be just as effective mitigation as mitigating the tank buster itself.