Redaction: Mormon’s “thus we see… ” is his signal of the main point: that “the Lord worketh in many ways to the salvation of his people.” He draws this conclusion after pointing out that more were converted than those they killed. Regardless of the historical issue about sources and numbers, Mormon extracts a theme that supports his greater purpose.
Literature: There may originally have been a stronger contrast than our current text suggests. The first two phrases are meant to be a contrasting pair:
“not a wicked man slain…
“but…
“more than a thousand brought to the knowledge of the truth.”
The contrast is between the slain and the converted. One set dies, the other has eternal life. The negative construction “not a wicked man slain” begs to be paired with “a righteous man given life.” While the phrase “more than a thousand brought to the knowledge of the truth” is not as clean as “a righteous man given life,” the meaning is virtually the same. Perhaps a tighter parallel in the original did not make it completely through the translation.