People hyped about Dancer and here i am drooling for a Gunblade Job.

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Anyway, let's consider this for a moment, the Girl in the Trailer is Garlean.

Garleans seem to use a mix of Jobs instead of just one.

Let's take a look at Livia:

http://finalfantasy.wikia.com/wiki/Livia_sas_Junius

Livia is shown to be highly proficient at hand-to-hand combat, her weapon of choice being a pair of gunbaghnakhs. She incorporates both rapid and powerful punches along with swift kicks and gunshots into her fighting style. She is also shown to be proficient at piloting magitek armor.
Mix of Two Jobs, so it might be that the Girl in the Trailer is a Garlean and a mix of Monk and Dancer? It would explain the Monk skills used along with the Cloth Slashes.