I kind of agree with this.
WAR being able to heal other party members MAKES NO SENSE. No part of its class fantasy is "healer". It SHOULD have decent sustain, but as you say, reducing/shielding incoming damage (largely to itself) should be how that works.
Conversely, part of PLD's class fantasy IS that it has (a few) White Magic spells. Basically Cure 2, Holy, and Glare, which is what Clemency, Holy Circle, and Holy Spirit are, respectively. The first should be (and is) a DPS loss to use since you're trading a turn of damage for a turn of healing (to speak in classical FF game terms), while the latter two should be DPS gains over your normal attacks at the cost of MP. Which they are: 1-2-3 has an AVERAGE damage of 300 per hit (900 for the combo of 3 strikes = 300 per hit averaged out), of which Holy Spirit does 350, so a slight gain, which is upped to 450 used as Divine Might procs. This is a pretty good system. Largely same deal with their AOE: 1-2 averages 135 per hit (270 for the combo) vs Holy Circle's 200 when buffed. ARGUABLY the base damage should be 150 (> 135) not 100, but the general point still comes across well enough.
The self-healing of those spells probably should be lowered a bit (since Holy and Glare aren't exactly known for their healing), or alternatively, the healing removed but Clemency being given some kind of Holy Might effect to let you use it for sustain for big pulls where damage is less important than sustain and enmity (e.g. wall-to-walls). Though on that point, PLD should REALLY get a low level (like level 30) pre-Clemency that upgrades to Clemency later (like Rage of Halone into Royal Authority), considering a lot of lower level content, PLD has no self sustain. It has no sustain until Clemency at 58, and none as part of its rotation until Holy Spirit at 64.
Contrast the other Tanks, where WAR and DRK get theirs at level 26 (Storm's Path and Souleater), and GNB gets its at level 4 (Brutal Shell). This gives sync or leveling PLDs (*cough* Palace of the Dead solo runs *cough*) a far harder time of it. And before you mock PotD - note that there was a time when PLD could Cross-Class CNJ abilities Cure, Stoneskin, Protect, and Raise (though didn't get the trait to use it in combat). So pre-SB PLD runs of PotD, they'd have Cure, Stoneskin (10% HP), and Protect (10% damage reduction) availble to them at those level ranges where now they have nothing of the sort.
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As to the thread as a whole:
- GNB was in a pretty good spot, so not sure why they changed it. Maybe had something to do with TOP since the forced downtime favored DRK but hurt the other Tanks, including GNB?
- PLD needed a buff, and I think everyone knows that. It was doing EVEN LESS damage than BEFORE the rework, which made no sense as the rework was (partially) supposed to address how it was already doing too little damage. It somehow got even more button bloat but did even less damage. So the buff was absolutely needed, there. PLD was the RDM of Tanks (and arguably still is), but unlike RDM, it's actually getting some buffs to bring it in line to where it should be.
- DRK was already doing fine. DRK struggles in easy content, which isn't so much "struggles" as "actually needs a Healer", which isn't some damning indictment on DRK so much as it is on the other Tanks having too much sustain/healing. DRK didn't need any buffs (neither did BLM), as it was already the gold standard and the "automatic pick" Tank for most high end content with the other slot being a contest of GNB (which usually won) or WAR (if you needed more flexibility) or PLD (if you didn't have either of the other two available). DRK got a longstanding problem fixed (Living Dead) and in such a way that actually makes it a powerful and useful CD now, and it has an extra personal mitigation vs the other Tanks as well. DRK has been eating good this expansion.
- I have no idea what is going on with WAR, though. WAR is a Tank, party healer, and now DPSer all in one. It's like Vanilla WoW all over again if Warrior was ALSO a healer. It's frankly ridiculous at this point. While it IS true that WAR's self-sustain isn't AS big of an issue in high end content as it is in 4 mans, it wasn't super far behind DRK/GNB, so the damage buffs might have over done it. And they also did this after the last couple patches of buffing WAR's healing - the Divine Veil change was needed, the Shake It Off change was not. I honestly have no idea at all what's going on with WAR.