I proceed from the assumption that as knowledge workers our primary job is to communicate. Communication is not overhead, it’s the work. Things like writing code are reifications of previous communication. The quality of the code mirrors the quality of the communication and comprehension that precedes the generation of the code.
Ross Mayfield pointed to this article on effective reading and I found the quote from it above very applicable to the work of most product managers; especially when it comes to gathering requirments and writing specs. I think that is why having a codified process in place is so important. The fear is that it will be too rigid and will slow the development process down, but the fact remains, the more time you put into the front of the project communicating with developers, you increase your chances of success.