The WoL is a blank canvas intentionally, so that your imagnitation can fill in such blanks. Your character in this game is not a fixed character with a complete background story and thats by design.

I'm not a roleplayer, I dont have a background story for my character but I still dont want to see such a quest. Or maybe I also dont wanna see such a quest because I have no backstory for my character and suddenly being confronted with "Here! This person has known you since you were little!" would feel completly weird and out of place.

Furthermore this game doesnt tell the personal story of your character, unlike other FFs. Your character has excatly the story you give him or her - all those questions you bring up are questions that you can answer yourself, answers you can choose for yourself and answers that fit your narrative best.

Vidu doesnt has a backgroundstory, she doesnt need one and I dont want to be forced into one. I dont want to follow a questline into a village to meet two generic Roegadyn, claiming to be the parents of my character, knowing that every other Roegadyn will meet the excat two NPCs. (Or hears the same story about how your parents died from a generic NPC.)
It would take away more than it would add and would leave a bad taste in my mouth.

Its an intresting storytelling "idea" in a game that has a definied maincharacter. This game does not.
I wouldnt mind seeing such quests for the more important NPCs - and we learn certain things about some of them already!

But my character is mine. I get to tell her story, if I wish to. I admire the writers of this game, but they wont write my story.