I've taken quite a few university genetics courses and have done some lab work as well. I personally find Judy's guide fine.
It's not suppose to be a text book. It's suppose to be guide. A cliffnotes of sorts.
While it doesn't go into depth, it does introduce the basic concepts of what is going on in Ball Python morphs and breeding. And for people who have never taken a formal genetics class, that's really all they need.
If you're not satisfied with any of the guides provided, then I encourage you to write one yourself. If it's good enough, perhaps it could be stickied.
^^ This is true.