In writing a fictional story or any piece of literature, one always needs to have the opinions of the audience in mind. One of the main things that influences how successful a piece becomes and how the audience receives it is the mindset that the author has while writing it. That is especially true for mormon literature, as much of the world does not understand or is not familiar with our religion. Mormon literature seems to be almost frowned upon, when the author makes blatant references to the mormon church, people will generally have a different opinion of the book.
The amazing thing about fictional mormon literature is that the author can tailor it to his needs, whereas a non-fictional piece of literature cannot be changed as much to fit the religious background of the audience. For example, sharing a personal story about conversion to the church or a principle can be a scary thing, putting your feelings out on the line. With fiction you can share your story but possibly change it to fit the general feeling you want the reader to have. Also, the author can change the story to add a lot of mormon influence, or a little, or not even mention the mormon church directly at all. Fiction allows the reader to become more immersed in the story, and the the author can introduce themes about the church in a more subtle undertone.
In the book, "Will Wonders Never Cease" by Douglas Thayer, the author chose to introduce the church in a more up front way, and that was his choice to make it a prominent theme throughout the book. This allowed him to slip in ideas about serving missions, baptism and conversion easily throughout the book. While some prefer this more in your face method, others may prefer to leave it as a more subtle undertone throughout their work.