Intertextual Connections
Dozens of examples of intertextual connections can be found in the Book of Mormon, when a writer or speaker refers to the words of another writer or speaker, often without directly referencing the original source. A (growing) list can be found here.Geography
The land of Nephi, first occupied by the Nephites and later occupied by the Lamanites, is higher in elevation than the land of Zarahemla which is to the north and separated by a wilderness. This is very consistently described through the Book of Mormon.Movements
Multiple interwoven storylines
The Book of Mosiah, for example, is complicated.
Editorial Promises
The appendix at the bottom of this BOMC article offers a long list of editorial promises embedded within the text. Many of these are details promised in the ancient section headers which are fulfilled within that same section. This is to be expected, and so I won't focus too much on these. Other editorial promises (which I find much more compelling) are offered up in the text itself and then satisfied many pages later.Each of these elements adds to a long list of details which the author of the text must have kept track of. Any theory of origin which limits the production of the text to Joseph Smith dictating with his face buried in a hat should account for the presence of these details, whether by divine or natural means.