Sounds good. Do any of these also go into why specific ingredients work best for certain styles?
Yes, that's exactly what Designing Great Beers does.
But as I mentioned, due to the lack of many ingredients years back, there are work arounds you wouldn't have to make today.
Not sure I get what you are saying here. Just because we have more grains and hops to choose from we can't use this book anymore?
DGB walks the dog through many of the basic processes of the brewing day, it also gives you a great foundation on how and where all the "numbers" come from, and then why they are important.
I guess in the end, it comes down to where and what you learned the most from. I have been brewing for almost 8 years, and did not read the Joy of Homebrewing until last year, I don't feel I missed out on anything. I used the online version of How to Brew, but have never read the whole book.
Every time I feel I need to look something up in a book Designing Great Beers is the first on I pick up.