The main difference between the 2004 book and the newer material is, you are no longer "stacked" perpendicular to the pool bottom in Fish, Skating, and switch drills. Although the purpose of having people that stacked was probably exaggeration to overcome old flat swimming muscle memory, it tended to produce over-rotation in the actual swim stroke for some people. Another difference is that the recovering arm comes up wide for the Shark Fin/Zen drills, instead of up the side - it's now Zen Switch instead of Zipper Switch. This was to give a more natural angle for the shoulder, with less impingement.
Other than that, there isn't a huge difference. Some of the drills that were dropped, I am now doing and finding useful. They were too tricky for the beginner that I was back then, but are do-able now that I have gotten a little more advanced.