1. Preaching OT narrative (at least as an expositor) should be done in the same manner that any text should be preached, regardless of its genre. In my opinion, the goal of expositing any passage is to preach the divinely-inspired meaning as intended by the author of the written text. I know that is simplified and opens up a whole discussion of hermeneutical issues, but such a goal seems reasonable to me.
2. If preaching OT narrative is nothing more than preaching the meaning of the text in the same way that a passage from a NT epistle (or OT prophet) would be preached, then it seems to me that the issue really comes down to a lack of ability to read OT narrative properly. I.e., the problem is methodological (in relationship to exegesis) rather than homiletical.
3. Homiletically, a sermon from an OT narrative may look very different than a sermon on 1 John, but the goal of preaching the meaning of the text is the same. Thus, the real question that this and other posts are addressing really needs to be, How does the expositor discover the meaning of an OT narrative text? Said another way, Where is the meaning found?
I have developed certain ideas about this issue, but I would like to know what others think about the merit of these thoughts.
In my opinion, this question is the most misunderstood part of the whole equation. Until we as preachers and teachers understand the biblical intent of these OT narratives as part of the scriptural text the issue of homiletics really is beside the point.