Totes truthsies? I never finished VI or XII, so I don't have the necessary nostalgia needed to properly appreciate the Garlean Empire. That said, I never really cared for them beyond as a starter villain in A Realm Reborn; they're very clichéd imperialistic villains, outside of supposed concern for the environment (that they despoil by way of ceruleum extraction and refinement, in addition to exacerbating the primal problem).
For the record, I've never been fond of importing characters or grafting locations from previous games into XIV. The standout example is the Return to Ivalice raids and accompanying characters, which I emphatically did not like. Also I do like IX (even if it has some serious flaws), but that doesn't mean the second half of Dawntrail isn't derivative of it (though not necessarily bad) and by extension predictable.