Uh, yes, it's a Dancer.

If any of you actually watched the trailer closely, you could easily draw the conclusion. If you watch the trailer again at 0.25x speed when they start fighting, a long red sleeve comes out her gauntlet as she swipes down on him. Also you'll notice a "Golden" line as well which would be the hidden blade. In FF Tactics Dancers used "Cloth" as a weapon or dagger in other instances, this incorporates both. Some people say "Oh but she's using Monk moves", Dancer is a subclass from Monk, duh. Others speculate "Red Mage" being released because Yoshida said something about Scarlet Witch. Obviously it's not a coincidence that the chakra of said dancer is "Red". Yoshida could be playing mind games.