Lee Eclov has some excellent thoughts on modern fallacies of preaching, and the value of exposing listeners not only to the point, but also how you got there:
Picture a wilderness. A pioneer carves out a path, chopping away brush, felling trees, marking the way to a new outpost. As years pass, that path is traveled a thousand times till it becomes a wide, paved road. From it, other trails branch off, leading to other new outposts. Trails intersect, becoming crossroads. More outposts become towns. More trails become roads. More links are made till what was once wilderness is civilized.
Preaching is the work of spiritually civilizing the minds of Christian disciples. Preaching—especially expository preaching—cuts truth trails in the minds of our listeners. Our task is not only to display God's "point," but to instill God's logic—how he gets to that point.
For example, we do not simply preach the conclusion of 1 Corinthians 13—that "the greatest of these is love"—but we move people through the dimensions and definitions of love in that great chapter. We show that Paul intended such love be not only at weddings but also at church meetings as well. In other words, we not only establish the outpost—"the greatest of these is love"—but the truth trail as well.
Preaching, ultimately, needs to be an attempt to map the mind of God as revealed in His word. Sometimes the purpose of a sermon may be no more than that, but as our goal is to be conformed to the image of Christ each new understanding brings us that much closer.