What is wrong with Wiegers’ classification of requirements?

Panel discussion

The classification of requirements given by Karl Wiegers in his book “Software Requirements” is well known to most analysts. This book, thanks to its popularity, has become a kind of Bible for the analyst, and the classification of requirements has entered most courses on business analysis.

But when analysts try to use this classification in practice of different types of projects, they often face difficulties. I propose to dive into the analysis of these difficulties to get understood what is wrong with the Wiegers’ classification of requirements, and how it can be improved.