How a Shapeshifter Could Work in FFXIV

[Shippuu]

By that loot pool logic, we shouldn't have DRG.* Or NIN.* Or any melee in Heavensward since each one of them had exclusive gear, so that's not really an excuse.

Except that's not how it works and you know it. DPS jobs having their own individual gear worked at 2.0's launch partially because it was a holdover from 1.0's days. Those jobs have their own tier of gear because they must and are staples of either FF games, or Fantasy RPGs. Ninja follows the same way, as claimed by yoshida was a rogue class staple that he felt was necessary to any successful fantasy game/setting. There's also the likelihood of a longer term plan that intends for NIN to share gear with a future job (Dancer comes to mind) so that it remaining it's own set may simply be temporary, we don't know.

Most of the jobs added since then could have easily had their own tier of gear, samurai, red mage, etc. But they don't because from a developmental standpoint it's a bad idea. They have enough problems creating the art assets alone as they re-use the designs for every set of gear and that's with a tremendous amount of gear sharing. It's more work for the devs and more of a pain for the players as the loot pool would become ever more polluted.

As for an option to use DPS gear, have a starting trait put in that increases Vitality and defenses while increasing Tenacity by an amount equal to Direct Hit gained from gear and adjust potencies to compensate for the increased damage caused by dealing magic damage.* Other features can be balanced passively, so it's not really that much of a nightmare for balancing.

It absolutely is not that easy. You can't just handwave it away saying a passive would cover everything because these stats aren't always static uncreases. That's not even touching the complication of looking at gear that shows direct hit but when worn on a tank it's actually being converted to tenacity. The skills have different stat weights and it could seriously cause other issues such as when it comes to melding. From a coding perspective it's preposterous to demand such extra hidden systems to be developed for a single job for literally no reason when they can simply be developed to wear appropriate gear.

This can also create terrible balancing issues if the job shares gear with a dps, as adjusting one stat for a tank can buff or nerf the dps side too much. That's not even talking about the asinine notion of a tank having to compete with dps for equipment in all content.

As for a tank dealing magic damage, we now already have two of those,

There's a huge difference between a job that deals SOME magic damage, and a job that deals ONLY magic damage. DRK is already at a disadvantage in the situations I mentioned, but they're still capable of fulfilling their role adequately because their main form of damage and enmity is not hindered.

Glad you pointed out we have 2 magic themed tanks already, showing the redundancy of creating yet another one.

which tells me that not only would mechanics revolving around opposing magic damage not be as big of a thing, but devs would probably know how to implement them in such a way that that sort of mechanic would not apply to any job in a tank role and could potentially retroactively adjust what fights have these mechanics accordingly should there be enough demand for it.

And there it is, the need for special exceptions. At that point, the tank isn't dealing magic damage then, they're dealing special kind of damage that only they can do, at which point there is zero reason for them to not simply do the same type of damage the existing tanks do. Special damage and exceptions makes for harder balancing which they already clearly have problems with.

Of course if devs happen to be as inept as you seem to imply them to be (which I definitely don't),

You can be optimistic all you want but they're still humans who have very busy work schedules. Their choices with tank balancing for 4.0 have been incredibly questionable and there is no denying it.

With the whole "being different" thing, look at SAM. Everyone was expecting it to be just like the armored tank of FFXI, but Yoshi decided to have SAM as something different, and despite the whining and moaning at first, people enjoy it now.*

Oh look, now who's speaking on the behalf of a demographic? Irony.

but there could just as easily be a tank that breaks that rule, much like a DPS that can heal.

As we established, no, it is not something that is easy and comes with many, many, many complications. At least the way you're trying to put forward.

If what you say is true and more caster players would favor it than tank players, then guess what?

Dude, listen to what you're saying. The demographics just aren't there. Tank player retention is arguably more important than trying to lure new players into the role. You'd be taking a massive gamble that simply isn't worth it. Only if the entire caster population switched to it would it then be worth it, or even half, but that's not going to happen. Realistically you can't force people to play roles they don't like. Even then, the larger dps demographic is still melee dps and even your mage tank still has melee combos. There's more to caster players than just wanting to do magic damage and wearing a robe, it's the playstyle of having actual cast bars which doesn't work all that well for a tank and is already covered by paladin.