The 1830 typesetter removed the adjective wild that modifies the following noun wilderness, probably because he considered it a redundancy. One possibility is that the original manuscript (which is extant and reads wild wilderness) represents a dittography—that is, the scribe, Oliver Cowdery, accidentally first wrote the wild of wilderness, then wrote the whole wilderness. There is, however, little evidence for this kind of dittography in the transmission of the Book of Mormon text. It is possible for such a dittography to have occurred at a line break (that is, with wild at the end of a line and wilderness at the beginning of the following line). But in this instance, wild wilderness is found in 𝓞 in the middle of a line. More generally, we do not find dittographies where the first part of a word is repeated as a separate word.
According to the Oxford English Dictionary, the word wilderness is related to the word wild and refers to a region untamed or uncultivated by man. Given this meaning, the use of wild with wilderness here in Jacob 7:26 is a clear redundancy. But a related meaning listed in the OED for wilderness is a desolate, uninhabited region. Given this meaning, both wild and wilderness could co-occur without redundancy.
The phrase “a wilderness” occurs in 2 Nephi 7:2 and 2 Nephi 24:17 (both Isaiah quotes), as well as in the book of Ether:
Here one can interpret the wilderness as an untamed region (since wild animals inhabited it) and also as an uninhabited region (since no people live there). The reference to the northern region as being “covered with inhabitants” seems to emphasize that the southern region is uninhabited. The word wilderness can therefore be used to specifically refer to an uninhabited territory, which means that “a wild wilderness” in Jacob 7:26 can be interpreted as a wild, uninhabited region. Consequently, the critical text will restore the original, difficult reading in Jacob 7:26.
Summary: Restore in Jacob 7:26 the original phraseology, “a wild wilderness” (the reading of the two manuscripts); this phraseology can be interpreted nonredundantly as meaning ‘an untamed uninhabited region’; the repetition of the morpheme wild does not have to be interpreted as a dittography.