I have to say, even scrutinising the fastest clears on Midas Savage at our present gear levels, there's still a surprisingly high tank stance uptime divided between the two tanks in A6S and A8S, so there's actually a lot of potential room for improvement. It's not simply a matter of turning off tank stance and pressing a six button rotation. Active mitigation is still important to keep you out of stance. Either way, I suspect that the PLDs who are pushing the envelope on the job's dps probably aren't the ones complaining about its damage output in single target.

I also note that a number of the fastest clears don't necessarily have a NIN present. It's certainly nice to have a NIN, and you should certainly take advantage of their skills when present. But by no means should you ever be reliant on another class in order to perform one of the minimum competency checks of your role.

Gearing for Parry is only bad because it requires you to give up more useful stats with better scaling. Block and Parry are not intrinsically bad. There is a very obvious difference in the total damage taken in a fight with physical autos when you compare PLD with any other tank. This becomes more pronounced the longer you spend actively tanking, and is no small part due to having a shield. It may be difficult to appreciate this in the short term due to stochastic effects, but when averaged over a large number of attacks, these "random" procs become much more reliable. There was a really good update to our understanding of block and parry on reddit earlier this week. It's probably worth checking out if you can dig it up.