But you get to nearly full MP at the end of Requiescat. Yes, you still need a chunk going into it. But not nearly as much as used to be needed. Yes, Clemency isn't unlimited - but you can use it with far less penalty.
Because Requiescat and Sword Oath have windows within which you can do their actions. The timer limits that somewhat but you have flexibility on when to execute those actions. It's not the end of the world to lose a GCD.
But as I've said repeatedly, I still realize that losing a GCD is very bad, particularly in a highly optimized raid scenario. So my emphasis on those other things was that it can be done without losing a GCD anymore. I mean, why spend for clemency when Requiescat is spamming self heals on you anyways and holy shelltron comes up so often?
The GCD option is there. And more usable than ever. But not ideal and anything that takes a GCD never will be ideal, I'm not disputing that part. But in less than ideal situations, it's more healing with the tons of healing PLD already has.
And if we're going apples to oranges, Shelltron also gives guaranteed block (19% damage reduction whenever I use it, not sure if it varies based on stats), +15% flat damage reduction, independent of the standard tank CDs of course, and can heal the whole party (minus oneself, which is an odd quirk yes) even if it can't increase the barrier strength... and so on.
And, honestly, speaking as someone that plays healers too - if you're on warrior, your healers might still prefer you use regular mitigations on tankbusters, because a lot of warriors try to use holmgang where it isn't absolutely needed and it just increases the healing requirements (which translates into less party DPS by increasing the healing load). But, yes, warrior can cheese tankbusters/tank swaps slightly more often.
And then DRK over there doesn't have nearly so much, and has the highest invuln heal requirement, but has high damage.
And maybe warrior does need to be toned down a bit, especially in dungeons. But PLD is strong. Maybe not in damage, but overall, it is strong.