I know what you're thinking. One thing? Yeah, there's plenty to be bothered by, but today something else occurred to me that I hadn't specifically put my finger on yet.
In addition to the anachronisms, the incorrect flora and fauna, the lack of women, the blatant copying of the Bible (including errors)... one thing that's always bothered me is that the Book of Mormon seems to be written for a modern audience. In general throughout the course of human history, no one ever writes anything for the benefit of those in the distant future or past. And I mean no one, except Doc Brown. Pretty much everything is written for the benefit of those who will read it in the present or very near future. This applies to everything in the Bible, everything written on cave walls, papyrus, giant stelae, the Internet... everything. You just don't see people composing novels specifically for the benefit of their extremely distant ancestors.
But when we examine the Book of Mormon, which was allegedly written about 2600 years ago, we find that it is constantly referring to Christianity, and specifically to 19th century theological arguments. It doesn't seem to be written for the benefit of the ancients; it consistently and explicitly refers to those who will eventually read it in the distant future. It even goes so far as to explain what "reformed Egyptian" is, and what the brass plates are. If it were common for ancient people to write in Reformed Egyptian on brass plates, there would be no need for the author to explain any of this. Even if it were rather uncommon, anyone reading the plates would obviously be familiar with both the medium and the language. So these explanations can only be for the benefit of a modern audience who is unfamiliar with such concepts.
It even explains who will eventually find those plates, what his name will be, and what his father's name will be. Is there anywhere else in Christian scripture where prophecy works like that? And why would ancient American Jewish proto-Christians care about the name of a prophet 2400 years in the future? Pretty much the entirety of 2 Nephi 3 (Joseph prophesying about Joseph son of Joseph) was either miraculous (and irrelevant to the ancients) on a scale that the world has never seen, or reflective of an enormous amount of gumption on the part of Joseph Smith. I am reminded of David Hume's maxim: testimony is sufficent to establish a miracle, only if the testimony's falsehood would be even more miraculous than the fact it is trying to establish.
To me, the observation that the Book of Mormon was written specifically for a modern audience is good evidence that from the perspective of the Book of Mormon's author, that audience existed in the present, not the distant future.