I would very much like to see a personal quest implemented along with a bit more background/personal story integration. I've seen this done in a couple games in very limited capacity, but they added nice flavor (imho). DAI: background generates quest for your advisors on the war table, Mass Effect has running content between the first 3 games depending on your origin.
I could see it being attached to our background ex. Criminal has to finish a heist to get help from their contact or get kicked out of gang, Acolyte must help a follower, Noble restoring family name, etc. One for an entertainer could be very fun if Bards make it to the game as a playable class.
Another option is attaching it to our bio. But at the moment our Bio is pretty generic. When I look at the tag for [CUSTOM] it just says we are an eager adventurer. I think it would be great to give several bio options here instead. Not only for a personal quest but also to help determine overall motivation for the character outside of the main quest for the full party. Ex. Start over somewhere new, Seeking Revenge, Keeping a promise, seeking a relic, etc.
I did notice some dialogue options resulted in adding tags to my character. ex [Baldurian], and in DOS2 [Hero] so maybe we could even pick up a personal quest from several different NPC depending on those tags that would allow a custom character to grow.
All that said, I agree it pretty late in the game to do something that is likely very challenging. And even if it doesn't happen, I'm enjoying the game. Still adding my vote to this in case it issomething they would consider, or maybe even something that might one day make it to an expansion pack that allowed us to continue our journey assuming we survive this one.