Dramatica doesn't know anything about the subject matter of your story. There are no right or wrong topics or themes. It doesn’t determine the commercial nature of your story. Dramatica only deals with issues at a structural level. For example, Dramatica may assist you in structuring your story so that you main character has a problem of "disbelief", but Dramatica doesn’t know how "disbelief" will be expressed in your story. That's up to you and outside Dramatica's structural view of your story.