So if a Gunblade Job is introduced into FF14 how do you think it will function as a Tank or DPS?
For me....
As a Tank I see it as a Job that may take into the design of a Gunblade. What type of Tank is a mystery since not much I can think about beyond taking advanage of the Gunblade's design of Melee and Range combat. Their Pull skill is a bit obvious being their basic Gun Shot skill. I only see gunblade more as a Tank Job due to how it shown currently in FF14. Not to mention SE and Yoshi-P seems to enjoy placing any Jobs related to Swords as Tank Jobs for some reason currently.
If it goes to a DPS Role, it may mix the combination of Melee and Range attacks for their Damage. Splitting their combo types into a Melee combo path for more focus damage and a Range combo path for their condition damage. Maybe add some special mechanics that takes into account Gunblade's Sword/Gun Nature for some of their skills or their combo attack.
(I would have made a SAM post but I'll just leave that until SE finalize SAM since originally it was going to be the Tank Job of 3.0 until they switched it to Dark knight and how Yoshi-P said he saw it more as a Melee DPS Job so what Job role it will be we will just have to wait and see the final product in a future release.)