More ideas for smaller differentiations that can more easily be moved towards:

1. Tanks are differentiated in 3 key areas: Minor CD, Invulnerability, and "extra" style.
2. For the minor CD, DRKs gets the strongest, but with an extra resource. Warrior gets the weakest.
3. For the Invulns, Paladin gets the strongest, DRK the weakest.
4. For the style, this balances them and is built to augment the way the CD and the invuln fit into the job.

Dark Knight
- TBN CD removed
- Manacost kept
- If not procced, puts a free Oblation onto the target after it runs out
- Damage of most attacks reduced significantly
- Most attacks now apply 3s of a DoT
- This is the same DoT for all attacks, it stacks in duration
- This DoT heals the DRK for each tick of damage it deals
- Living Dead blocks incoming healing, saves it, after it runs out or when it fires, the deferred healing is applied as a HoT with a 3s-60s duration based on how much healing was blocked (caps at 100% of DRK HP = 60s HoT). Most self-healing after proc removed in turn (needs active healing again).

Warrior
- Bloodwhetting healing normalized and as a result massively reduced.
- New trait: Unstoppable Berserker. All damaging attacks cause some damage-based amount of self-shield. These shields stack. Essentially just hitting target makes you ignore a non-trivial amount of damage, all the time.

Paladin
- Bulwark removed
- Wings is now a 2,5s cast (with bar), then lasts while you can do other stuff, so long as you don't move from a tiny area at the front of the wings.
- Intervention damage reduction improved, but that extra reduced damage is Cover-like moved to the Paladin.
- Block-force added to Shield Bash: Raise Shield, if hit during the GCD will auto block, then hit back with damage based on blocked physical hit damage + stun + 10 Oath Gauge. Shield centric tank, blocks damage for others, uses shield actively as a combat implement.

Gunbreaker
- Little to do here, already strong and with quite some flavour to its style and CDs.
- All attacks can now be done from 25y range, use a different animation if used as a ranged attack. 100% uptime tank, basically. Lightning Shot removed since it's no longer needed.

I would also urge them to consider removing Rampart. Or rather, upgrading it into the job-specific ones, then introduce the minor CD earlier, and focus way more on that, not only giving the triple-effect version at 82 or so. Simplify those effects, but also give it all very early. Including TBN and so on. Make the minor CD the "default CD", not Rampart.