According to J. N. Washburn, there is no more convincing evidence of the variety of material and structure in the Book of Mormon than the difference between the records of Ether and Moroni. Just turn the page, and the change hits the eye forcefully. And yet both came to us from the same writer, Moroni, son of Mormon. The book of Ether is narrative almost throughout. That is, it is narrative with rich commentary in pertinent places. The book of Moroni contains no narrative at all. The nearest thing to it is in chapter 9. [J.N. Washburn, The Contents, Structure and Authorship of the Book of Mormon, pp. 70-71]
Another interesting difference between the actual writings of Moroni and his abridgments was pointed out by E. Cecil McGavin in a series of radio talk over KSL radio in 1941. According to Brother McGavin, the term "and it came to pass" is used by Moroni 117 times in forty pages of his abridgment of the records of the Jaredites. Yet in thirteen pages of his own writing, consisting of over 7,000 words, he does not use the expression a single time (Quoted in J. N. Washburn, The Contents, Structure and Authorship of the Book of Mormon, pp. 160-161).