Wait, WAR with notable self sustain? WAR's self-sustain is a joke outside of using IR to spam Inner Beast/Steel Cyclone.
Especially compared to DRK whom has TBN as well as DA Souleater which does appreciable amount more than Storm's Path.
Are you referring to IR? The skill that is necessary for WAR to use to maximize DPS? Or Holmgang that's necessary for WAR to keep for Tankbusters in order to do the things that everyone complains about WAR being too good for?
Or are you referring to PLD's Tempered Will which is a skill purely available for knockback prevention that doesn't cost them another powerful CD?
The difference is how they perform that burst. WAR's rely entirely on IR and FC spam in its duration, this is a 90s CD. They have little set up (Only needing to make sure that Storm's Eye buff has adequate duration) and little cost (Since it takes no resources and in fact gives a bunch of CDR to Infuriate)
PLD has Requiescat which is a 60s CD and relies on Holy Spirit spam (Currently. There's nothing to say they couldn't get an additional offensive spell to use with it. Or even get an Oath Gauge spender that deals damage to make use of the Oath they generate while spamming HS). It has the set up of requiring 80%+ MP in order to get the effect, as well as the cost of using up a bunch of MP to spam the necessary skills. One (Or both) of these aspects could also receive a change.
DRK has Blood Weapon which is a 40s CD and boosts their SkS and gives them additional Blood generation... They just continue to spam their normal skills but more frequently rather than having a 2 button combo that sets up and then gets mashed for DPS. It could be adjusted to have more impact and a higher CD and still be different in that they wouldn't just mash 1 skill for the duration like PLD/WAR (With aforementioned possibility for PLD to also get a more diverse "Rotation" as part of Requiescat)
No you wouldn't. You'd still see favour for burst because how it lines up with CD's.
Unless you gimp the "Burst" jobs sustained DPS to laughable levels. Which, would include PLD because they're also a "Burst" job as they rely a lot on their Requiescat CD for a significant amount their damage, just like a WAR relies on Inner Release.
DRK is really the only Tank that isn't so burst orientated at the moment, because they don't have such focused damage boosts (Blood Weapon has a 37% uptime for example). Ironically, they're also the tank with the closest DPS to that of WAR...
So... Make Tanks rely more on the generic Role Actions skills?
Rather than you know... Removing all of the Role Action CD's and instead relying on classes having their own, unique CD's that let them specialize in certain situations? Such as Dark Mind letting DRK shine vs Magic damage and WAR having Raw Intuition letting them shine in single target Physical situations (Due to no longer having Awareness to negate the downside that comes with multi-target situations often having attacks that come from the sides, or spells that go straight through the parry chance)?
So... Homogenize tanks even more?
No, the problem is that people aren't considering the fact that WAR isn't the epitome of Tanking. It merely excels in the meta that has existed. Where Raid damage is often irrelevant outside of Tankbusters, where Holmgang shines and where WAR's lack of consistent mitigation (Through not having Shelltron/TBN or a Defensive stance with Mitigation on it) is irrelevant.
Where DPS is the only concern for a Tank and as such WAR, the more offensively tuned Tank, thrives, especially with the way buff stacking works (Including Slashing debuff. If Magical debuff was as prolific as Slashing, you'd see PLD on top because then their Requiescat bursts would be far stronger)
Thus, mitigation is not a concern, so DRK/PLD whom have better mitigation than WAR don't shine. Support is not a concern, so PLD who has Cover, Intervention and Passage of Arms doesn't shine.
Where the fact that WAR kind of sucks in OT roles because all it provides for support is the AoE shield (Which, to be honest, I do feel is a skill that can be culled from WAR, it doesn't really fit with them. In addition, it actively powercreeps off Divine Veil...) is mitigated because you just toss PLD there...
Alternatively, the solution is sit back, look at everything that makes WAR systematically dominant and look at the tools other Tanks have and why they're not as strong.
Look at why WAR's DPS is so good when PLD is also burst CD based too (Also, why DRK, a not as burst CD based job outperforms PLD)
Look at why WAR's have good snap threat, while PLD/DRK less so despite their kits being so similar. (Though, personally I actually find DRK the best for snap threat because DA Plunge/Dark Passenger is an oGCD high enmity generator. With toggling off Grit also not requiring a GCD allowing for high initial threat without much cost)
Look at why WAR's are seen as the best mitigators while PLD/DRK have more consistent mitigation skills (Hint: It's because damage is designed in a way where it's all about tankbusters and where things like Shelltron/TBN/Inner Beast as well as defensive stances are not particularly notable)
Look at raid utility and how WAR's are seen as good with their Slashing debuff (That's also brought by the NIN that people prioritize for Trick Attack and threat for non-WAR comps) and AoE shield while PLD/DRK are not (When PLD has a ton of selfless skills)
There shouldn't be flat out buffs or flat out nerfs. There should be tuning. Tuning up things that are weak. Tuning down things that are strong. Tuning certain utilities that happen to work well with specific things (Like, ironically, PLD coincides better with DPS CD's since many are on the same 60s CD compared to WAR's 90s IR CD). Tuning content so that it's not nearly as focused on specific things (I.e. Tankbusters that require "Supercooldowns")