It seems that generally the designs for Paladin and Gunbreaker are quite well received, they're the least complained about tanks, and most complaints about Gunbreaker are related to the sound effects change that happened some time ago. The real controversial tanks that people feel are heavily homogenized are Warrior and Dark Knight, and its quite obvious the biggest problem here is new Delirium.

On a surface level I understand the purpose of new Delirium: It's a regular burst phase not based around pooling MP for raid buffs, and pressing 5 Bloodspillers in a row helps break the repetitive 1-2-3 gameplay of Souleater combo that has plagued the class since Stormblood. The issue is, even if a spammy phase was what the developers wanted to add... why does it have to "5 gcds every 90 seconds" just like Inner Release? It happens too infrequently to successfully break the monotony of spamming your combo, and because it's the same gcd 5 times, it ends up feeling monotonous itself, specially because Bloodspillers animation is clearly not designed to look good when spammed! I feel like something as simple as "Delirium is every 60 seconds and is only 3 gcds long, Blood Weapon is every 40 seconds" would have given Dark Knight a more distinct feeling and addressed the 1-2-3 problem better (given that they seem committed to not giving DRK a secondary combo ender for DPS for whatever reason). In addition, the cooldowns on Dark Knight's non-Edge of Shadow offensive cds are way too long, and further contribute to those lengthy windows where you have nothing to do besides press 123. Another DRK rework is something we're unlikely to see for another 2 years, but switching around the cooldowns and durations of certain skills to make the class feel more active is not beyond the scope of a major patch. If Dark Knight's identity is to revolve around a low button count GCD rotation with plenty of off-gcds, we need shorter cooldowns on the off-gcds.

Warrior is a bit more of a problem to diversify away from Dark Knight largely because it seems they intend for it to be an inherently simpler class. It seems Warrior's identity is meant to tie heavily to GCD skills, sorts of like Black Mage or even Monk. If that's the case then Warrior would benefit heavily from having a higher diversity of weaponskills. I think the core foundations as they are aren't too bad, but perhaps 1 or 2 more skills on the GCD could serve to differentiate Warrior from Dark Knight further, albeit I'm not sure what form those skills could take. I don't want to say "add a dot" because that feels extremely unimaginative and is just a timer to track, so perhaps Warrior's identity will require another expansion to flesh out.