I posted this ages ago in another thread but it seems like no one is mentioning chemist. This would also be a great addition to the current roster.

Chemist would give us another healer, just not a mage type. Chemists also use guns.

They could use potions and such as consumables. Maybe have an ability to throw a potion high over a party and shoot it, shattering the glass and making the potion aoe. Traits to make them more effective. Theres alot se could do with chemist in ffxiv. Its sad that such a great and useful job in fft hasnt been used since.