Well I hope it happens either way, I would rather give us some more indpeth backstory to what happen to kaguya before she at the fruit because it's pointless to showcase Kaguya significant change after eaten the fruit that made her fall in the pit of darkness when Hagoromo was questioning about it. So I don't see how in that aspect gives more retcon.Because their answers might make even less sense. They run the risk of making the Kaguya arc more ridiculous. And regarding the loose ending.. that's kinda what Naruto Gaiden is for.