Ya Know....

[Dualblade]

But there is no way in hells the gunblade job will be tank. Gunblades have always been two handed weapons. Or used with no off hand at least (Jake is the only exception who dual wields.)

FFVIII: Squall used his with two hands, Seifer with one hand.

XIII: Lightning used hers with one hand.

XIV: Gauis/Regula/Fordola/random Garlean commanders use their's with one hand.

Thancred: Shown pulling out a gunblade about the size of a PLD weapon, which is one-handed.

In Dissidia Squall also uses his gunblade with one-hand quite a bit.

You might be JUST a bit off-base about gunblades always being two-handed.