Well, yes, there is a lot about Kaguya's backstory which was left ambigious at best, but I don't see how it will be cleared up now. The right point to show indepth flashbacks about her past seems to have passed already. I really would like to be proven wrong in the next chapter though...We didn't see the sealing happen on-panel like with Black Zetsu. There is still the mystery regarding her fusion with the tree and motive for wanting chakra which only Kaguya knows about.