I don't get the argument of the Shaw force ghost not making sense because he never existed that way. I mean, it's a very common idea that the souls of those in the afterlife are the manifestation of the last currently known living form of that person only healed from wounds and injury. I admit that the theory of returning to a younger and more active "age" after death is also a common theory, but it doesn't fit the rest of the evidence presented in the movies. Ben appears looking like he did at the age that he died, except that he's not cut in half, the injury he sustained that killed him. And Yoda is presented at the age he was when he died, except he didn't seem ill. So that theory holds itself entirely consistent. To allude to the other popular theory of, "George had to use Shaw because he didn't have a young Anakin yet!", there was absolutely nothing keeping Lucas from having the Shaw ghost appear as the burnt and bald inside the suit Anakin. As we'd already witnessed that form, we know there was nothing that would have prevented him from reusing it if he wanted to. But he chose to have the perfect representation of Anakin at the age that he died, just as he had with the ghosts of Ben and Yoda. And now his meddling has made his entire logic of Force ghosts completely inconsistent.