DRK still sacrifices a resource to empower it's abilities. That's like saying DRG isn't accurate because it's jumps don't avoid damage. Bards have used bows in past FF games (Not counting FFXI), and they still pull out a harp for all of their songs. Zeninage could easily still be added and it simply not actually cost gil, just like how BRD/MCH don't actually have to have ammo, and WAR's get to throw their weapon and it magically returns to them, same with PLD's shield, same with DRG's Piercing Talon, or NIN's Shuriken throw (Death Blossom too).
That's not even touching on the developmental issue of thinking of adding a job that needs multiple weapons. Does it need to equip multiple weapons? That's 2-3 weapon models that need to be designed each patch for just 1 job costing more in art assets/programming for drops (unless it uses other job's weapon appearances for it's secondary weapons, but then how is that countering "homogeneity"?) If it only has a primary weapon, and the secondary weapons are just generic models then that's a pretty poor cop-out. People already complain about the MCH aetherotransformer and the AST's card sleeve being static and unchanging no matter which weapon they equip.
If they want to add a multi-weapon using job, they're better off creating something new or picking something that's better known for using multiple weapons, not butchering a job's classic identity.