I sure with the critics would try to come to a consensus on who wrote it.
Even mormon Apostle B.H. Roberts conceeds that one of the other writings in existance at the time, Ethan Smith's View of the Hebrews furnished structural material for the bom. Roberts admited that the evidence pointed in this direction:
It has been pointed out in these pages that there are many things in the former book that might well have suggested many major things in the other. Not a few things merely, one or two, or half dozen, but many; and it is this fact of many things of similarity and the cumulative force of them that makes them so serious a menace to Joseph Smith's story of the Book of Mormon's origin ... The material in Ethan Smith's book is of a character and quantity to make a ground plan for the Book of Mormon (B. H. Roberts, Studies of the Book of Mormon, 2nd edition (Salt Lake City: Signature Books, 1992, p. 240).
In this case, it is a mormon with integrity who points to the clear evidence that smith et.al. came up with the material for the bom from existing sources, and not a mythical set of golden plates (that mormon history itself indicates were not used).