Re: Fatal Flaw?
Sure I can give you some more examples that aren't adaptations:
As mentioned above, "The Lives of Others" (Das Leben der Anderen) which won the Oscar for Best Foreign Film in 2006 has a split Main Character and Protagonist. "The Counterfeiters" (Die Falscher) which won the Oscar for the following year also has a split between the two (notice the pattern?). Both excellent films.
Back home, and more recent, you would have "Zombieland." The girls are the Protagonists trying to reach the safety of the West Coast, Columbus (Jesse Eisenberg) is the Main Character - he's the one we empathize with the most and experience the story through. The original "Terminator" also has the roles filled by two different characters. Reese (Michael Biehn) is the Protagonist trying to protect Sarah Connor (Linda Hamilton) who is the Main Character in the story. Again, we see the film through her eyes, but it is Reese who drives the efforts towards the story goal.
And, of course, there's always "Casablanca." Viktor Lazlo is the Protagonist pursuing those papers and a means to escape. Rick is the Main Character through which we witness the story ("Of all the gin joints...why did she have to walk into mine?")