1) I agree that the magic of the first three films has been irrevocably lost. Although I am one of those who loved ep 3 when I saw it, there is NO going back to what Star Wars was in my brain before these new movies were made. I would go back if I could.
2) They tried to give people "high language" in this one, which deals, among other things, with a lack of contractions. Ewan took awhile, but in this film he nailed it and the dialogue sounded natural even though it was "high." Portman never mastered the skill, so she just sounds unnatural with the language. I believe that is the failing of many of the actors. Picture Samuel L. Jackson doing Shakespeare. Is he comfortable onstage? Can he express himself through the dialogue? Star Wars is not Shakespeare, but re-structure the sentences and remove contractions and, as far as the actor is concerned, it might as well be.