I don't find the tanks all that different from eachother in terms of damage rotation.

WAR feels like a slower, more boring Dark Knight that centralizes entirely on one attack. People like it, I only think its a fun job defensively, offensively its very boring.
GNB feels really strict for the sake of it, it feels a bit clunky to me, and I've generally disliked super rigid rotation jobs. Continuation is fun to press though.
Can't give much feedback on PLD, I didn't enjoy how the job played before with how many hoops it had to jump through to do basic things, and I havent bothered to try it now.

Dark Knight is a weird one, and the one I've put the most time into. I like its completely flexible rotation mixed with high apm gameplay. I like how it mits in savage fights, how much power comes from its flexibility in mitigation there.
I do not like how dull it is post burst windows, I dont like how overly centralized it is around Living Shadow, that skill drifts like nothing else, and is already "late" to any buff that only lasts 15s. I dont hate it like others do, but it definitely needs something to round it out. I don't agree that MP management isn't a real factor at the highest end, it definitely is, and I'd argue that DRK has to watch its gauges harder than any other tank.
Its not just a factor of don't overcap, its find a spot before the next burst window to pick up a Dark Arts stack, and still have there be enough time to generate the mp you spent on TBN back before the burst window, without overcapping.
Similar situation with the blood gauge, you need enough to mash living shadow on cooldown, but not enough to cap but still can bring an additional Bloodspiller into a burst that way. Darkside is the only resource that isn't really notable as a thing you have to really try to upkeep.

Its AOE game is also a mixed bag, I like the fact its the only tank thats frequently mixing AOE types (Lines for Flood/Shadowbringer, Circles for everything else). But then you get issues like Abyssal Drain, which is just comically underpowered for the role its trying to fill. It either needs a shorter cooldown or 2 charges, but now that its stapled to Carve and Spit, its very hard to buff it. Honestly that skill needs to be reworked entirely, probably back to a GCD.
Living shadow is also really awkward in AOE, its borderline not even worth using, as it only has 2 aoe attacks, takes forever to get out, to the point where mob packs are usually dead by the time that it does, or in the best case scenario it gets its aoes off then burst down one guy, who would have died with the rest to the aoe spam anyway.

I like how it plays more than the other tanks at the very least.