Here's my perspective, being a beginner -- I would be turned off by a book that was too step-by-step or too directive (do this, then do that, etc.). I would much prefer a book that gave accurate scientific information in a way that was easy for the novice to understand (in my opinion, some of the hardest kind of writing to do!) so that I could then apply those principles to my own tank, my own tap water chemistry, and my own ideas about what plants, fish, inverts, etc. I want in my tank (not to mention apply them to my own budget!).
For me, one of the most interesting parts of this hobby is all that there is to learn -- not just about "what do I put in my tank to make my plants grow" but about botany, animal behavior, freshwater biology, bacterial growth, chemistry, and more. If you took that part of the hobby away by oversimplifying things, I don't think I'd find it nearly as fascinating, and I certainly wouldn't learn as much from it.
What's more, with my very hard, very high PH tapwater, a "one size fits all" beginer model would have me adding quite a lot of additives to my water to attain an "ideal." With 20% or more weekly water changes, those additives would quickly add up to a lot of money. The likelihood of a PH crash or other instability would go up, and so would my likelihood of failure.
Plus, without that knowledge of chemistry, biology, and so on, when something DID go wrong, I'd have to go back to the book to troubleshoot instead of being able to interrogate the problem independently. That also leads to frustration -- I don't know about others, but if I feel like I'm just blindly following someone else's system without a sense of the whys or hows of the thing, I really feel uncomfortable.
So just my 2 cents as a beginner, but my preference would be for a book that gave a beginner the science he or she would need to understand what's going on in the planted tank and the ways various factors interact so he/she can make good choices, but also some been-there-done-that advice to avoid common pitfalls. Perhaps some advice for getting started relatively cheaply, but building in the opportunity to upgrade over time, since cost is an issue for a lot of beginners? For example, I started with low-light (and a few "didn't know better" higher light) plants planted in Flourite and gravel because I couldn't afford everything I wanted for my tank right away and I figured it would be easier to upgrade my lighting later than to change out my substrate later. And the book would have to have lots and lots of pictures, of course!