I don't know about in general but here's my Ideal "tanks"

General: Rampart Removed (30/40s get to be 90s), Tank passive gets nerfed down a bit. All invuls 30s apart Holmgang = 270 / LD = 300 / Bolide = 330 / HG = 360

Paladin
Offensively - Bring back combo paths, keep the Divine might buff have more focus on GCD gameplay, I think this tank just become the interesting GCD tank with some ogcd's. Blocking attacks could also lead to "shield swipe" which would be a very small potency ogcd, Holy spirit should upgrade into holy circle should be learnt during ARR. (Remove the passive where mp cost is halved and just have all magic spells halved to begin with)
Defensively - Change how blocking works tbh it's a very out dated boring mech, Bulwark could be swapped out for something more interesting depending on how blocking would change, Removed magic attacks on the job, Holy Sheltron - 20%, still grants Knight's benediction but for 18s, Same with intervention (regen to normal sheltron added just way weaker), Cover should grant targets a small regen or mitigation and not cost gauge, likely give it a longer cooldown.

Warrior
Offensively - Just add more things to beast gauge, this job is fine being simple.
Defensively - Passive inbuilt max HP by 15% with, Short CD should be split into two that share the same recast, one being a mitigation for 15% that targets you or a ally, second should be a heal that acts like the healing effect on blood whetting (can only be used on self), the main difference being that you dont heal per enemy, Equilibrium shouldn't have a regen attached, shake it off should be swapped out for a Mitigation on party members (it makes no sense that warrior healing allies), Vengeance Upgrade should just be 40% instead of having a regen. (yes this is a lot of healing nerfs on warrior but the max base HP should help warrior out, and it still keeps most of it's sustain).

Dark Knight
Offensively - Fast paced with ogcds, I'd likely give it two combo paths, a small haste buff (somewhere) just in general something that feels different from warrior, bring back cool animations like Power slash PLEASE)
Defensively - it should Remain mostly the same, I think oblation could do with a small 150-200 potency life steal effect (Don't make it per enemy like current warrior), just because the cooldown feels kinda bad (its new excog could be changed out or reduced), Dark Mind should be 15% but grant something like a 5% physical mit, Dark missonary should grant barriers to party members instead of being a mitigation cooldown

Gunbreaker
Offensively - stays the same.
Defensively - 5% Hp buff (similar to war but way smaller), HOC should be 20% 6s and the Excog should be around 700 potency HOL should work on physical, rest should stay the same.