Market requirements documents (MRDs) can vary in length from just a few pages to hundreds of pages. Almost everyone in the organization dreads a long MRD. The product manager hates writing it, and everyone else hates reading them. In many cases, long MRDs simply go unread.
Your product manager should compose MRDs that people will read. If that means a more consise MRD, so be it. A product manager can pack a lot of useful information in an MRD that's less than twenty pages. And some of the "boring" information, such as quantitative data (e.g. market survey results), should go in appendices.