Samurai

[Miggiwoo]

Could we possibly be looking at a hybrid class? Swordsman base class, with ability to split into either DPS or Tank based on soul.

I think that there is one archetype of tank not explored - similar to BLM. Essentially have some abilities move through add stacks of a stance that reduces GCD and applies dots for DPS, and increases parry & evasion for tanks, and some abilities either remove stacks of this or add stacks of a strength buff that increases potency and applies non-damaging debuffs for DPS (vulnerabilities etc) and increases flat damage reduction for tanks, but by a lesser amount than parry & evasion. Tie the effects of cooldowns to it as well. Maybe add an ability that can transfer your stance on a long cooldown.

This would also be in stead of a dedicated tanking stance and in my view is more organic than a straight up stance dance - both stances have defensive and offensive benefits and are more or less comparable but with each stance being optimal for different situations.

[Shurrikhan]

Could we possibly be looking at a hybrid class? Swordsman base class, with ability to split into either DPS or Tank based on soul.

Could always have a bit more of a F/SN type Assassin, paired against Samurai and based off of Ronin, but I also don't see why the job needs to be wholly limited to one or the other even if Samurai was that only choice. There are plenty of ways to limit simultaneous role usage without having to give purely defensive CDs, forcing the job into a tank role, and then inflate certain potencies to rebalance its dps potential (Fell Cleave, Royal Authority, Salted Earth...), for instance like what you mentioned below, though without each necessarily having to be multi-role, or even being limited to personal dps and personal survivability.

I've always imagined Samurai as, for a lack of a better role term, a Strike Leader, some blend between a Commander (having a toolset that helps to direct the flow of battle, sturdiness to stay in the thick of it) and a Commando (having a toolset that synergies well with offensive focused pack strategies and allied cover, personal survival 'tricks', and agility enough to stay at the head of the offensive). That partly means "tank", I suppose, and also partly "dps".

If you could imagine a Dragoon as being able to interrupt enemy attacks with the majority of its attacks and capable of more charges per minute, and able to actually tank lesser adds efficiently (between its defensive CD coverage and swapping out via Elusive Jump), that would probably be its closest niche. A Deliverance-happy Warrior (who still knows how to tank damn well while in Deliverance and is just barely willing to swap into Defiance as necessary) would be the second closest.

Durable and highly skill-based, with a lot of thinking required to have the right defenses up at the right time. A tiny bit less dps than Ninja, and more than Bard/Machinist. Not a "tank" (as it lacks any pure defensive CDs, many being dual purpose, such as crit/accuracy and parry/evasion being wrapped into one CD, e.g. Third Eye) in title, but can definitely tank when there aren't too many tank busters present. (Though very high knowledge of the fight could make up for even that.) Perhaps able to equip tank armor at cost of attack speed, cooldown speed, or the like, though only really necessary when trying to be a real tank.

Consider the trouble they had with ACN branching into dps/heal, I doubt they would do that again.

They're always free to redesign the class to job relationship. More importantly, they don't necessarily need it to be consistent.