While you tried to explain the differences, you didnt list them all, even some of the important ones, while mentioning ones that have 0 impact on encounters, playstyle, or player choice. (Such as WARs having the most burst. Which USED to matter when content actually favored burst more.)
Due to tendentious, I'll not go into the details, despite saying you failed to do the same thing.
In short, most tank DPS is a playstyle difference. (most notably WAR and DRK being nearly idenitcal, but the playstyle is easier to execute for DRK, and easier to understand, along with being faster due to more oGCDs. PLD has a full on rotation. GNB can essentially be boiled down to, when shiney button is ready, press is. (priority system)) Functionally DPS type means nothing. Only the rotation, and how you interact with it, or not at all.
But the largest differences between the tanks in what they bring to a party, is their raid wide mitigations. (which has subtle differences, despite mostly being close enough to the same thing) Mitigation ends up being what matters most, but functionally in a players decision making process, and what it means for your party.
Otherwise, the next biggest difference is how their "non rampart/30%" mitigations work as a whole.(Example, DRK has the least number of mitigations to use for trash pulls, but has the best TB mitigation. PLD has the 2nd least trash pull mitigations, but has the best party raidwide mitigations. GNB is a bit of everything, but not the best at anything)
IMO they are 2nd place, but close.
oGCD usually boil down to "press when ready" but for PLDs case, they cant/shouldnt do that for physical/magical phases when it comes to FoF, or Req. So thats 2 points PLD have over DRK. (maybe 1, since both have to press their DPS up buffs, the difference being timing requires more thought, before it becomes muscle memory)
it doesnt matter if its single target or AoE, oGCDs need to be keep on CD as soon as possible, w/o a DPS loss being incurred, which means salted earth will functionally be no different than circle of scorn. Nor CnS vs Spirits within. Abbysal drain is essentially a CD for mitigation, as well as DPS, so this is a bit of a grey area. u can argue its 1 more oGCD to make AoE DPS complex, but realistically should be used for survival, like aurora is used on GNB, and Equilibrium for WAR. You even use it in single target scenarios, because its always a bonus, so it's not something id personally put into the "makes AoE DPS more complex"
But then again, this is coming from someone who doesnt feel muscle memory means a rotation is less complex, because you have it down to memory. (example, the number of holy circles before you use confetior is down to muscle memory, but in the begging, you have to watch the mp/timer, to try and make sure u land confetior, or count out the number of presses. which imo is different from looking to see if an ability is lite up or not.)
The line AoE matter less, due to 2 things that all tanks do;
(1) dodge circle AoEs. Which has u dancing outside their circle, and always pointing inward.
(2) pass through trash mobs, and have them face away from the group.
if those 2 things werent done regardless fo which tank you were on, then id give a point to the line aoe requiring more work.
also, for the quietus spam, the ability lights up, so i once again feel this is a lot more straightforward, despite it seeming more random, than the phases in PLD. (But ill agree this is up to opinion) However, I do agree they come close to eachother, regardless of which you feel is more in depth.
Luckily FF14 never did that, cuz i hated that in other MMOs, including vanilla WoWs sunder rule.
But when tanks had to handle threat, they never needed DPS not to do dmg. the only thing they needed DPS not to do, was pull. (and that was mostly 2.0 as a non WAR)
Otherwise the tank had the option to use more threat moves for a DPS loss, or in some cases/expansions, DPS had an option to lower their own threat, while maintaining their DPS (and no DPS loss! No holding back!) The problem is, out of those 2, we know which people complained about more, despite one of the 2 is a DPS loss, and only one of those should seem like the viable option.