They would never be complete or fetch all possible scenarios.
The same thing can be said of first aid kits, but it doesnt mean that rhey are a bad idea.
Better learn your tools of the trade and configure what you actually need.
I've been doing networking and computer security for a couple of decades. I've seen a tremendous number of security flaws that have resulted from basic misconfigurations, misunderstandings, and even typos. Making cofiguration of routing and security more complex and manual a task than it needs to be reduces security.
But maybe you can help me out; where can I find a good packet flow diagram for the various routing, NAT, and filtering components that make up pfSense?
It's a security product after all.
Its also a routing product and that's the functionality I'm talking about.