One difference between Mormon’s editing of the large plates and what we saw from the writers on the small plates is that Mormon spends more time on the battles and wars than did those earlier writers. Perhaps this was due, in part, to the fact that the large plates were intended to record the wars and contentions of the people, and, therefore, more of that information was available.
Perhaps Mormon’s career in the military made him more sensitive to military matters. In spite of the larger amount of writing about wars, it isn’t typically the wars themselves that interest Mormon. He is interested in the people involved in them, and the lessons to be learned from them. In this case, he notes that Alma himself leads the armies, and the Nephites began to defeat the Amlicites. Of course, that was due to Jehovah, who “did strengthen the hand of the Nephites.”