I do feel like one character that should have some focus is you, the WoL him/herself. We really don't know much about our own avatar. The first scene in the game. Why was s/he on the cart to begin with? Where was the WoL's original home? Was s/he leaving there because at the time the WoL literally had no fighting capabilities? If so what if s/he went back now as a god slayer?
What about old friends from those home that s/he might've known before meeting the Scions?
Hell how about encountering a character that if you are starting from ARR is a legendary WoL and you want to know more about the guy and his struggles during 1.0 or if you are a Legacy character that NPC is instead one of your comrades who fought beside you during Bahamut's awakening?
Some stuff that focuses on the WoL I think would be great to expand the character. Moreso if you approach these as a Dark Knight and your Fray contemplates on how things have changed from before you went on that cart to now.
Thoughts?