Probably because Disney's facial CG sucks. You'd think with all of Disney's resources they be much better than they are. It's gawd awful. Nine was supposed to revolve around Leia's story of this trilogy (7 was Han and 8 is supposed to be Lukes). Obviously, that's in doubt, but honestly I think fans would be ok with some CG Leia if it were minimal; maybe similar to Vaders role in Rogue One. Well, to play devils advocate, the originals were never really mapped out either. Not knowing how it would do at the box office, SW was originally a stand alone movie. That said, it's 2017 and this is Disney, so you'd think they'd at least have the trilogy story on a napkin somewhere, right? Quite possible, but I'm going to give Disney the benefit of the doubt here. They can't "Disney" this property or I hope they don't. They do seem to have a vision for the SW franchise since this is now two movies they've parted with the director on. I have more faith in Kennedy than Disney. JJ would not be the right director for ep9 and I hope they stick with Johnson, but we'll see.