Nun chucks aren't a real weapon..
On another hand, Gunblades won't come unless we get to the point in the story where we start to use the Empires technology against them. Maybe a special muskateer weapon.

Katana is Samurai, and Wakizashi thingamabobs for Ninja.
Scythe is Dark Knight of course
Great swords we will probably see in the next job connected to Marauder
I assume Daggers will make a comeback with Thief
Gun is obviously Muskateer

This post needs more weapons that are less likely to already be in planning.