Playing as your kid is honestly pretty silly since it would basically mean all of the recurring characters would have to be immortal. Not to mention the weird shit that would come up like having a kid with a male Robin only for it to be high school aged when you play it and in the same class with its father who is also its boyfriend.
It will never work.
Lol.
One of the main reason that I'm saying it's for a very distant future it's how hard it would be to implement this. Basically almost everything in game would be changed, including the NPCs.
So, instead of Robin and all, we would have new NPCs.
But, we can very well use the same tropes, so instead of my lovely Kylar, my children would meet another yandere besides their mother. Instead of Robin, the children would meet another cute good natured person with a really hard life. Instead of Eden, the children would meet another lonely hunter. And so on.
The same applies to other things. Instead of being an Orphan, we could be trying to live on our own while our parents moved on to another city. Instead of a "caretaker" we could have a real landlord. Instead of all the conspirations about the lake, the Ivory Wraith, that shitty order that made my lovely Kylar suffer, well... That would be the hardest part, since we would need a new major "dark" plot.
But you can also be "lazy" and put the same plot but with new names. The same goes for everything, both the "I can't believe it's not the same" (just like reusing the same city and all but with a different name), and things "ok, I can easily accept it's not the same" (just like the characters that uses the same tropes).