This is how I understand Rosenthal's A.S.S.
(1) Approach = The angle (perspective) from which the story is told. R-Dawg calls this the "handle" or "key." Establishing the angle or "key" from which the story will be told gives the script-writer greater clarity on how to address (or approach) the story and its purposes. Therefore, the key helps define the movie's purpose. Rosenthal seems to suggest utilizing non-gimmickry, so as to attract audiences with fresh perspectives not anticipated, overused, or expected approaches.
(2) Structure = The means by which the movie's story unfolds. In other words, the movie's framework. The structure of a film shapes the film's argument to achieve the film's purpose. Rosenthal mentions how there are many paths (means) for a filmmaker to take and still reach the same goal (ends). He said the nature of the movie's framework can be natural or invented. However, I suggest the film is always invented. Here is why: Film, as a medium of communication, forms an argument. The argument is structured in an order prescribed, visualized, and authorized by the filmmaker. Even if the events naturally unfold, the framework is still created. Consequently, the film's structure depends on how well a filmmaker can organize, construct, and communicate an argument.
(3) Style = The manner by which the story is expressed. Expression is important because it conveys the story purpose, which influences, impacts, and (re)shapes the audience's heart and conscience. Rosenthal seems to think that incorporating "style" is incorporating humor, shock, or nonsense. However, that is just one end of the spectrum -- whatever happened to seriousness, tensions, or dissonance? Filmmakers must fully utilize freedom and imagination to express the nature of their films, as Rosenthal suggests. For the expression can either enhance or distort the film's purpose, directly serving the audience for better or worse.
