I have found that grammatical errors are common in self-published books because authors do not go the final step to have their work professionally proofread. As for the other claim that the book "is a litany of report writing mistakes," this assertion seems to be a reference to either poor organization or ineffective stylistic choices for informative writing. I do not know exactly what you mean though because you do not provide any examples. (Failure to provides examples in support of a claim is also a commom freshman writing error.)
Perhaps I should have clarified: a litany of
police report writing mistakes. These are the kind of things they teach in California POST classes as examples of what not to do because they appear so often in police reports. I thought I did include examples when I mentioned grammar and typos, but since you are (or were) a college prof I'll be more explicit.

1. Typos. "Brittan" on pg. 6 and 7.
2. Incorrect punctuation/apostrophe error. "I own several Glock's" on pg. 23.
3. Grammar. "Back up guns is a common discussion" on pg. 23.
4. Excessive commas/comma error. "I carry the Smith & Wesson, Chief Special, Glock 3 0, semi-auto." on pg. 22.
5. Incorrect capitilization. "Pete, a Sergeant and Seven year veteran" on pg. 8.
6. Homophones. "While your exiting your vehicle" on pg. 27
7. Run-on sentences. "If you live in this country and are paying attention, you should by now have concluded that, if you are relying on the government for your personal protection, your safety is as uncertian as my golf game." on pg. 7.
8. Poor flow/organization. The section on revolvers and semi-autos on pg. 18-21. Single action revolvers are explained but not double action. Double action semis are explained but not single action. Discussing blowback vs. locked breech designs before explaining semi-auto components. Talking about large framed semis just before starting a section titled "Large Frame Pistols".
As to the other issues raised, retention holsters, firearm modifications, night sights and lasers, belt holsters versus pocket carry with a J-Frame, caveats concerning +P+ ammo, and the use of tasers, these points are, I would assert, beyond the purview of an introductory book. Their absence in Murhpy's book does not take away from the primary objective of the work, and this objective is to introduce neophytes to the problems and concerns of handgun selection and concealed carry.
My take is this book utilizes a "start from nothing" approach and is intended to teach beginners everything they need to know on a given subject. Going into detail regarding blowback/locked breech is an example of that. Since that's the direction the author intends to take, I find fault where he does not adequately follow through on that implicit promise.
Pg. 35 contains a table of recommended ammo that includes several +P rounds. The worst offender is a .38 +P+ round. Since Bill recommends these rounds, he really should have included a warning about use of +P or +P+ in non-rated firearms.
In Ch. 13 Bill mentions alternative force includes pepper spray, impact weapons, flashlights and taser. The rest of the chapter is spent on OC with no further mention of the other three choices.
Ch. 14 is titled "Low Light Techniques from the SureFire Institute", but how can you talk about night shooting without mention of tritium sights?
I would argue that retention holsters are a subject most CCW holders don't know or think about but should. Maybe that's just me.
Guys like to tinker with things and a common trap people fall into is thinking better equipment will make up for lack of training. That's why I think it's important to discuss which mods can be useful, which to avoid and the potential court liabilities. I can't speak to the author's mindset but most departments have strict rules against firearm mods. That may have led to the exclusion of this subject--it just wasn't something that the author gave much thought to.
As I mentioned in my original post, the book does contain some useful information. But it didn't live up to its promise and could have been so much more in terms of content. The lack of good editing makes it more difficult to get at the good info it does contain.