Lots of cool ideas in this thread. And even more to explore. But, since I could spend all day writing class ideas, I'll keep my ideas short, without gory details.

- I think the Invulns should actually be homogenized. Their effect is just too potent for any real diversity that feels good. Give Hallowed Ground a more generic name and make it a role action.
- Rampart should then be removed from role actions, and each tank gets a unique version.
- Sentinel/Shadow Wall/Vengeance/Nebula should all be made more unique, but with one caveat: either all of them should be tied to the class's dps, or none of them. Vengeance being any part of WAR's dps is problematic when the others aren't. If they all are, you still have the issue with a tank needs to be MT to do full dps, though. But at least it's universal, and they all have equal claim on MT being good for them.
- As for making defensive abilities unique to the class, I would follow it along these lines: WAR are all about increasing max hp temporarily, with a corresponding buff to all incoming healing; DRK are all about getting some % of max hp as shields (or reducing incoming magic damage by some %, but I think this aspect could be dropped); PLD are all about reducing incoming damage by some %; GNB actually has no identity--it gets a little bit from each of the other tanks, which is unfortunate--but the names are all astronomy related in some way, or Heart related? Really not sure what you could do to give them a unique feel with defensive cooldowns.
- Offensively, I think PLD and GNB are in a really good place. As a PLD main, the only thing I'm not super hot on is how much spamming we do, but eh.
- I honestly think DRK plays mostly fine, too. I like the idea of changing Darkside to a Haste buff, as it makes Blood Weapon's current timer less problematic. Or they could just give Blood Weapon an 11 second duration.
- I also think Abyssal Drain is cool, but could use some polish. In single target situations, it's just a bit of oGCD damage and a negligible heal. In big dungeon pulls, it's decent oGCD AoE damage, and a big heal. But the recast is so long, that the heal is really just a couple seconds of breathing room at best. Also, a self-heal goes against the idea that DRK use a % of max health as shields. I'd change it from a heal to a shield (which probably means changing from a low amount per enemy hit, to a bigger amount regardless of how many enemies get hit), and maybe change AD to a Spell on the GCD (with a cast time?) but has a mana cost? Kinda like DRK's version of a Clemency? Like, it's not part of your normal rotation, but an "oh shit" button? All those question marks mean I don't know if this is actually a good idea, but it is *an* idea.
- Beast Gauge and Blood Gauge being identical, though, is a big issue. One of these needs to change. I think it should be WAR's Beast Gauge, as Blood Gauge currently feels thematic for DRK as their offense seems to be all about keeping their resources spent, so as not to overcap.
- Rework WAR so it's still about these big heavy hits, but rather than building and spending Beast Gauge, it's about keeping its "Berserk" buffs up, which is done by filling Beast Gauge to 100. Maybe using Storm's Path or Mythril Tempest as part of a combo while your "Berserk" buffs are up could allow you to do the big hit--Fell Cleave or Decimate--as the combo finisher. Or it could open up a new big-hitting combo (ie Inner Beast -> Fell Cleave -> Inner Chaos from Storm's Path or Steel Cyclone -> Decimate -> Chaos Cyclone from Mythril Tempest).

Getting into some gory details here, but:

- when you fill your Beast Gauge to 100 or more, it is reduced by 100 and your "Berserk" buffs are refreshed. This language is specific for a reason: overcapping would not be an issue. If, for example, you hit 110 Beast Gauge, you would drop to 10 Beast Gauge and refresh your buffs.
- the "Berserk" buffs could be a few different buffs. Berserk would obviously be one (which would need to change for balance reasons--maybe just a bonus to Crit and/or a Haste buff), and maybe that's the only one required for Path or Tempest to get you to the big hit. Storm's Eye could be another. Maybe even Thrill of Battle, but has its % toned down (though you would need a corresponding % buff to incoming healing to be baseline, not a level 78 trait), at which point a few of your defensive abilities would just be improving Thrill of Battle to higher percentages? You could even require the other buffs to have Berserk up to have any effect.
- This would also require Inner Release to be divorced from Berserk. Which is fine, because the class would have lost its "burst window" ability, and Inner Release could be that. It could just allow you to use your Big Hit (or start your Big Hit combo) whenever you want. Or give auto Crit/DHits. But this would not be something that gets refreshed by filling up your Beast Gauge.
- both the "Berserk" buff durations and the rate at which Beast Gauge is gained would need to be addressed. Sort of like MNK, you should have a fair amount of wiggle room for refreshing your buffs