It has always bothered me that Leia doesn't react over Vader being HER father as well! In the end when the ghosts appear she doesn't seem to care at all about Anakin. I would have added a more stuff about Leia and Vader.
Felt the same about the first film as well.. Luke finding out that his father was a mighty knight instead of a navigator and he's like : Uh ok, wish I'd known him.. Shouldn't he be more intrigued?!