Honestly I want to know about the rank and file Garleans, the civilians. The Garleans are a people beaten then elevated from the ashes only to be beaten again by design. The reaper questline and the 6.1 role quest gave us a little bit of insight into the lives of the normal Garleans and there's easily enough to add another dimension to them and there interaction with the enemy of there leaders, the WoL.
How would they react to the Hero of the Savages, are we the ultimate evil to a people who were bullied and discriminated for years by magic users? How many of the people are like Fordola and just doing enough to up there role in life, or how many people are like Rhitahtyn and have fully converted to the Garlean's side, or how many people are like the Domans who are complicit and beaten into submission, or finally how many people are like the people from Bozja and are ready to fight to the end.
They didn't live like any of the city-states of Eorzea and with there path of conquest, any of the non Garlean main areas could of been anything and shown different legions doing different things. Like how different the empire's soiders in Eorzea were from the ones in Doma. It just feels like a missed opportunity.
