As someone who wants a Midagr in XIV, I think it narratively works best on The Source. A Shinra-like would be a threat to The Source's lifestream, and as a consequence, the lifestreams of the surviving reflections, and thus higher stakes. I think XIV's Midgar could be a Garlean city, and hidden somewhere in Ilsabard or it could be hidden in Meracydia, and potentially have ties to Allag.
