How a Shapeshifter Could Work in FFXIV

[Shippuu]

The itemization alone makes this job problematic. Your solution of them simply adding a new type of gear because it's "easiest for you" is actually the hardest for them. It pollutes the loot pools unnecessarily for a single job for zero reason except that you want them to wear robes. Your other solution to have them wear dps gear, misses the itemization issues of sub stats showing you lack the foresight to see those major complications especially now that we have tank and dps specific sub stats that are only found natively on their respective role's gear. This creates a balancing nightmare that isn't easily solved without straight up ignoring sub stats which is a big part of this game's gear treadmill.

On top of that, the concept of a tank that deals purely magic damage is another problem. Outside or being much harder to balance damage wise with the other tanks due to inherent weaker magic resistance in most enemies, it also creates problems in content where enemies or bosses reflect or are immune to magic damage. You now have a tank that takes extra damage in fights like leviathan extreme, or that cannot tank some bosses such as the one in void ark depending on which one because immune to magic.

This is just trying to be different for the sake of being different for pretty much no reason. It may be appealing to people who like casters, but is a concept that generally isn't desired for the community who plays tanks. Combined with the incompatibility of gear and other issues, this would be a less desireable tank for anyone to play. Why gear just one tank when you can gear 3? There's many reasons the tanks all share gear and future ones will continue to do so as well.