Neither of the two alternative endings is satisfying, both seem rushed, but other than that the film can be regarded as a brilliant homage to the German Lefist films of Weimar Republic such as "Mother Krause's Journey to Happiness" and "Kuhle Wampe". Fassbinder's look at the possibilities of communism is obviously defined by the experience of APO and RAF and thus more incredulous than the films mentioned above.
This is a bit of a sequel to 'Why Does Herr R. Run Amok?" It's less about the murderer, and more about the havoc they create in their families. Mutter gets off on the wrong foot by inviting in the Parasites, I mean the Press, and it just gets worse from there on. Exploitation is the name of the game, and even family members get involved. For some reason he decided to pander to the Americans with his filmed ending.
Fassbinder's films are all, effectively, exploitation movies, since they deal with the exploitation of characters as a metaphor for German society. Like The Third Generation, Mother Küsters' is a brilliant lampoon of arm-chair terrorism, but also a heartbreaking character study, given a greater emotional weight by the remarkable performance of Brigitte Mira as the martyred matriarch of the title...
What comes to mind years later is the power of the intertitle/text on screen. What is not shown, only described, can sometimes be the most devestating (see In the Mood for Love's concluding seconds, or numerous moments in Berlin Alexanderplatz).
LOVED this movie. The concept is extremely engaging and fascinating to watch: A widow's grief leads her to communism and then to anarchism. Neither provides the comfort she needs. Unfortunately, everyone in the film -- including her own children -- is selfish. It sounds awfully serious, but it's really a dark comedy. I prefer the original, more extreme ending over the happy U.S. ending.