About CGI characters:
CGI characters in live action movies has always been a dicey proposition, and one metaphor for this is a pre-recorded magic act. The audience at home wants to be fooled by a variety of magician’s tricks, but they usually don’t want to be fooled by deceptive video editing or people who have been ‘planted’ in the crowd specifically for the trick. In other words, people want to be fooled in some ways but not in others. CGI for me too often feels like a trick of the latter category. Some computer generated elements are acceptable, even expected in movies now, just as flashy lights and graphics in a magic show serve to embellish the theatricality of the act, but when the act itself is a deception, this breaks the unspoken agreement between audience and movie.
That’s just a long winded way of saying that Tarkin and Leia in Rogue One felt like a deception rather than a magic trick. Furthermore, in the case of Tarkin, he distracted from the primary villain: Krennick. Vader is a special case, since he has always been played by multiple actors. As long as James Earl Jones provides the voice, I have no problem with him being a secondary villain.
As far as Leia in Episode IX, I think there are far better ways to complete the trilogy than turning her into a CGI puppet. I would rather watch the movie magic of our new generation of leads than the deception of a corporation with too much money and too little sense.