I was wrong, this is quite a good film. However, it is good mostly because the title is inaccurate, it is not really about Ethel as a central character. Although she is an interview subject, she is not very open, so her daughter is forced to focus the movie on other things, and ultimately the film is much more about Bobby than anyone else. Which is a very good thing.
Although some of the interviews of other family members are good, the thing that really saves the film is a wealth of home movies and other historical footage. It seems like the Kennedy family somehow always had the best photographers in the world following them around 24/7. And the footage of Bobby is both heartwarming and heartbreaking. I honestly think we will never see a politician like him again; one who is really in politics for all the right reasons, and who really cares about all his fellow people.
This movie is definitely worth viewing.