Quality of an architecture is defined by the weakest link within the whole set of artifacts created as part of an architectural exercise. Documentation is definitely one of those areas susceptible to negligence and as such impacting overall quality of the architecture.
Below is an extract of an interesting technical note explaining an approach of reviewing the architecture documentation and as such improving overall quality:
This technical note proposes a structured approach for reviewing architecture documentation. Given the critical importance of architecture to software project success, it follows that the architecture cannot be effective unless it is effectively captured in documentation that allows the architecture's stakeholders to understand and use the architecture in the way it was intended. The approach does not assume a particular architecture methodology or a particular architecture documentation practice, although it was conceived in the context of the International Organization for Standardization (ISO) Recommended Practice for Architecture Description of Software-Intensive Systems and the SEI Views and Beyond approach to documenting software architectures. Like both of them, our approach is centered on the stakeholders of the artifact, engaging them in a focused, guided way to ensure that the documentation carries sufficient quality to enable them to do their jobs and to help them point out gaps and weaknesses. Our approach is not intended as a complete framework for architecture evaluation; rather it is meant to be used within such a framework, when one is available.