You actually can DD as a Gladiator right now. Yes it does require cross-class skills but isn't what the armoury system is all about? You even have a few +atk bucklers to help you. Now with phys levels removed and static points allotment, it'll be a bit less viable, unfortunately.

Great Sword will most likely be GLA weapon. Expect those, if they are actually meant for a more DPS approach, to have the stats to be one the offensive side. Pop the right gear + abilities (and points once we'll be able to do some allotment again) and you'll be all set.

And there is also materias....