Honestly I wouldn't look too far into this, after all, Sophia has a voice actor...
Printable View
This pic kinda looks like the gate seen in the artwork
http://i.imgur.com/IcH6k7O.png
Also, I'm really like the Garlean non-military architecture.
We could also visit it as one of the first dungeons in 4.0. Maybe?
(I love the idea of breaking through Castrum Oriens as the first dungeon in order to get into the lands behind it. Unfortunately that doesn't really match with the goal of not having (all) expansion content gated behind the story...)