There are still some slight differences between the 4 tanks despite the complaints of homogenization. They all have Rampart (20% reduction) and a cooldown that reduces damage taken by 30%.

Warrior - they have the highest burst damage out of the 4. The beast moves can eventually inflict guaranteed direct critical hits using the cooldowns Inner Release (upgraded Berserk) and Infuriate. Inner Release allows the spamming of either Fell Cleave or Decimate about 4 or so times in a row to make the burst really high. This also grants them burst self heals that can be applied to an ally and themselves when they use Nascent Flash. Their main weakness is the Eye of the Storm buff only being applied with single target with the AoE only refreshing the buff.

Paladin - the DPS tends to be more steady for these guys as long as Fight or Flight and Requiescat are used properly. They have the best "cheat death" cooldown with Hallowed Ground with the ability to target heal allies with Clemency. They have more passive defense since they can block in addition to parrying. The block can also work on spells. Their cooldowns make them arguably the best towards protecting other members. The main weakness I can see is they don't have any GCD spells or weaponskills that can be used within combos without ruining it.

Dark Knight - these guys resemble Warriors in playstyle, but their DPS is a little more steady. Having only one single target combo also makes them relatively easy to start with. I find their base combos to be a bit higher than the Warrior's base combos and they can apply their 10% DPS boost instantly with Flood of Darkness (AoE offglobal) or Edge of Darkness (Single offglobal). Delirium allows for a similar burst phase like Inner Release, except there is no guarantee for those crits or direct hits. The shield cooldown "The Darkest Night" is considered one of the best short cooldown mitigations and it can be used on any target. For weaknesses, Blood skills are a bit lackluster without Delirium. The Darkest Knight barrier needs to be countered with a tank buster at the right moment or your mana just drains.

Gunbreaker - this one brags about having the highest average DPS out of all 4 tanks. This is thanks to their 30s cooldown combo that also procs the off global Continuation that acts like an off global combo. The Aurora HoT as well as Heart of Stone can both be applied to anyone. Their cheat death is similar to Paladins, but it reduces their HP to one. Some healers get heart attacks from this, so I guess this is the main weakness if the Cheat Death Superbolide is poorly timed. The other is they can get pretty jammed with off global usage while they use their 30s combo cooldown. You have to use Continuation after every GCD use of the combo cooldown or you lose the chance for that damage. Plan the 2nd off global wisely for this moment.