Here's the happy ending I see in sight:
3.2 - SE finally fixes the STR vs. VIT bullshit and makes it so that tanks have a single DPS ceiling and hitting it is a matter of skill and not gear just like on every other job in the game.
3.2.1 or something sometime down the road, hopefully sooner rather than later - WAR is sitting pretty right where it is now, DRK is doing the same, (and people have gotten their heads out of their asses and realized that a DK clone and partial-uptime SP clone that stacks with SP itself is more than enough utility for a tank to bring), and PLD has been given usable raid utility...
...What I mean by that is simple. Cover, Divine Veil, Clemency, etc... even all those things combined don't add up to the potency and usefulness of a single raidwide utility offered by another job of another type, like say BRD/MCH or SCH/AST. They're half-assed and don't give a party nearly the kind of mileage that AST cards, fairy buffs, songs, and turrets do.
PLD is not the "mitigation" tank. Its not the "protector" tank. All these claims have been refuted. What it could be said that it -potentially- is, is the support tank. Look at SCH. SCH is the healer equivalent of WAR. Its the "off-healer" with high DPS. Look at WHM. Capable of about the same DPS as SCH, but with a toolkit that lends itself more to "main-healer", thus the healer equivalent of DRK. Look at AST. Slightly lower healing/DPS output but with ridiculous utility (say what you want here, but I have one in my static and those fucking cards, holy shit. The buffs are REAL.)
I think the path to success and proper balance of the tanks is going to be to make PLD, somehow, the tank equivalent of AST. Its able to heal content just as effectively (just as PLD is able to tank content effectively) has a lower DPS ceiling than the other tanks (just like AST falls behind WHM and SCH), but brings proper raid buffs and utility in a frequently utilized and active style of play. I'm not saying give them cards or give them songs, but it should be something that directly contributes to raid DPS and raid resources.
PLD is not and never will be the "tank that allows healers to DPS" cause this is patently false, DRK and WAR can each easily find ways to grant their healers these same windows if need be. DRK MTs clearing Thordan right now are also clearly disproving the whole "physical fight=DRK dead in the water" thing as well. What PLD CAN and SHOULD be is the tank that offers sufficient utility to open opportunities elsewhere in the party.
Example 1:
Cover or Divine Veil or Clemency changed - replaced or combined with Apocatastasis or a reverse Virus clone placed on a party member, or a combat res. Party can forgo a caster, go full physical, group can bring a MCH that boosts the entire raid's DPS (sole exception of the DPSing healer) with its physical turret debuff.
Example 2:
Cover or Divine Veil or Clemency changed - replaced or combined with TP/MP regen or Balance effect added, party can forgo a BRD/MCH and bring an extra caster/melee which = more DPS.
To prevent these from being overpowered, they could lock them behind Shield Oath. SwO pally doesn't need nearly the kind of help that ShO pally does.
These are just examples and by no means well-thought-out fixes but I see something in this vein as being the only way balance will be achieved without the boogyman(homogenization)'s help, and are intended more to illustrate a point and NOT to say that they need those kinds of buffs/utilities or clones thereof, specifically. WAR like SCH is always going to be a sort of one-size-fits-all type of deal, but you can see parallels with DRK in that a DRK allows a group to forgo a MNK and bring DRG/NIN for their huge raid-dps contributions instead. PLD needs to offer these kinds of party composition opportunities but on a much larger scale, to make up for their lack of personal DPS (which DRK does not really suffer from in the aforementioned example), in order to be considered without robbing WAR or DRK of their individual niches as well.
TL;DR WAR's power is in its huge OT dps and utility, DRK's power is in its huge MT dps and utility, and PLD's power should be not in its own merits but on what it bestows to the party. Those buffs/opportunities it provides have to be as real, concrete, and undeniable as its own lack of DPS/utility currently is.