It talks about what not to do floorplan wise, why not, and what kind of things would improve it. That should give you the idea of how to design your routes.
How would you have rather seen that part been described? A step by step walkthrough of building a lay out?
Might have been possible although you need to keep in mind that it needs to be pretty universal. A CS lay out is not a Quake lay out... It is very hard to write something down that is true for -all- action and fps games.