@Yuni_Queen
No, I don't wish to add any new abilities -- if anything, I'd rather trim a few. Personally, I like to try to generate the most possible points of decision or routes thereof with as few buttons as possible. Or, to put it another way, I like to maximize the interaction or gameplay caused by each button, click, or keystroke. For that purpose, I'd be willing to scrap numerous potencies, and even abilities, as long as most of the enjoyed gameplay remains intact and what is added more than makes up for anything lost.
Just by sake of adjacent information, I prefer versatility over specialization; unless a spec contributes to that above ratio, I'd rather have one "spec" that can do everything, with many different equally viable "play-styles" therein. As it stands, each job has only one real playstyle. There are a couple differences that contribute less than 1% dps that can stand as 'play-style' preferences, such as staying out of WM until EA/IJ, even if it means popping a Bloodletter without WM's modifier, instead of just until the next oGCD or Straighter Shot, but optimal play leaves very, very little in question or to preference. I'd personally like to see multiple "ways" to play an Archer or BLM, where the faintly leading output 'style' is the one that requires the most from the player. That applies far more to DPS than tanks, or further to healers, at that point, but the same principle stands. It's for those reasons that I tend to dislike the cooldown system we have, even if I do at first enjoy memorizing when to pop which CD for which TB; ideally, each is popped as near as possible to its CD while maximizing the mitigation it causes, as to maximize its mitigation over time -- fundamentally that's plenty enjoyable, but the strategy of syncing arsenal to content only goes so far when the timings for said arsenal are absolutely rigid, and the content itself will often change pace with gear and strategy. In many ways I'd prefer resource systems or the like, in a sort of economy of mitigation, investment and consumption, or just anything that's a bit more flexible yet decisive, allowing for multiple paths to reach the same goal, with more nuanced advantages and disadvantages. I feel like that would be a huge opportunity for tanks especially, and one that hasn't been tapped into at all yet. I'm not saying I want all tank abilities to function in that manner, but some at least should, and its a lucrative avenue to walk down while looking for class uniqueness or identity among tanks. Coincidentally, I first started thinking about these systems when ability names for Dark Knight were first released (and before I had read their very familiar tool-tips).
Only loosely related... I personally feel that physical level and "optimal level" gearing should have remained; to dice up character progression each into separate classes unrelated beyond a few required cross-class skills such that a player who just defeated Bahamut must now face bloody battle against level 10 Diremites seems a bit... off, though not so much as the sheer disadvantage given to leveling and gearing up alt jobs in a game that touts its ability to "play all classes on a single character".
What I mean is that I'd like to go back to their traits and actually make something unique out of them, aiming for distinct class identity based on gameplay as it immediately appears and feels, rather than mostly just through its alignment against particular fights. In other words, fewer key, much more thematic traits. While some jobs would certainly benefit more from this than others (e.g. the more dull ones), I think it is both helpful and perhaps even necessary in the long run to really know what is intended and/or ideal for each class and be willing to craft unique gameplay components for each class to that end.
For instance, try to think of any given class as an assemblage of particular mechanics or themes leading cohesively to a combined class identity. I imagine Gladiator as being a pesky, hardy, and resourceful opportunist, excelling at controlling and eluding enemy pressure. To this end (resourcefulness) his Sword-based and Shield-based abilities might be on separate GCDs (Sword and Board), he might be able to hasten queued weaponskills upon target enemy attacks attempted against him (Contretemps/Countertempo), etc.
Paired with any variety of changes like native cleave (anything that looks like a cleave, is to some degree a cleave), enhanced block control, and/or enhanced utility in the form of stuns and pacifies, this could go as far as creating ideal play in manipulating enemy attack timings to best grease your own rate of attack, sometimes even drawing out of range momentarily to prep a counter, TP control, and management of blocks, dodges, and parries, while perhaps using bucklers for a quick, oGCD low-effect Swipe or tower shields for a much larger effect and/or slight knockback that clips into the following sword GCD. Abilities that would generally be used on CD with little additional thought could be trimmed or revised. Abilities with a flat and at first unnoticeable effect like Rampart can be given later and are also likely revised. In turn, give something like Guard as a shield weaponskill with a variable cooldown for guaranteeing blocks early on for added control and thematic value, and move Shield Swipe or a similar ability up. Bulwark itself could easily be a trait, allowing for a sustained, no-CD Guard at diminishing value (or initially reduced based on the amount by which your block roll fell short, and steadily increasing), or become a more interesting ability or proc such as by creating Shield variants of your (normally Sword only) weapon skills while active/procced.
In addition to that, let it pick from a variety of fundamental cross-class traits from other jobs, such as Pugilist's Feather Foot (trait) -- which in turn synergizes well with the ability -- or Archer's Trained Precision (from Heavier Shot, now working to allow criticals to increase critical chance further into the combo or whatnot), Lancer's Drive Chain / Weapon Rush, Marauder's Bloodbath (trait), Rogue's Blindside or Assassination, etc. Inversely, Pugilist for instance could likewise take traits learned from Gladiator, such as Countertempo to pair into off-tanking or leveling, or any of the others.
The jobs themselves would then have further trait opportunities, though they'd of course lose some cross class trait ops. Paladin for instance might have a trait allowing blocks while casting, or have its spells factor from the greater of either its physical or magic damage and duplicate a portion of other main stats unto Mind, while carrying a native Cover trait (reducing damage dealt to allies behind you), etc.