Password restriction rules are Vogon. The initial problem is that people choose simple passwords that are easy to remember. It’s like locking the screen door to let in the breeze. But when you restrict the universe of passwords that people can choose from you make it easier to hack. The fallacy is to apply the tougher passwords to the original universe of all passwords. People are still going to use passwords that they can remember within the more difficult rules. If you dumped the password files in the more restrictive environments you will find the same amount of redundancy.
Before you start counting up the permutations, consider your own passwords, hopefully you have more than one. I’m sure that several of them are clever phrases that you believe are unique and fall within the restrictions. mIright?