If I were a superintendent leading the updating of our district vision and mission, I would embed that discussion in a conversation about kids. I would use the concepts from the NASSP's Breaking Ranks II book. Even though this is designed for high schools, the concepts fit K-12. The focus is on developing children for their future and shaping the purpose and the actions of all staff around creating what they describe as a school [district] that "will be a learning community that reflects a culture born of respect and trust, where the spirit of teaching and learning is driven by student inquiry, reflection, and passion."
Several years ago, our then superintendent was new and went through this process. He brought in an author who led a small group of district staff and community members in a book study as a means to revising the vision and mission statement. By the end of the several month process, most of the community members and many of the district staff had stopped coming to the meetings and in the end the vision and mission statement were developed and written by a very small group of administrators and a few teachers. Surprisingly, the mission statement is good, "Inspiring Excellence". It is simple, straightforward and although it was argued by some, I believe that it is indisputably what every school district should be doing. If you are not trying to be great, why exist and you are doing not only the children, but all future generations a disservice.
The process that I would use would be to gather as many people from staff, community, parents and students as possible. Have a few listening sessions and a short survey to gather information, then hold a work sessions with representatives and hammer out the statements. That would be only the tip of the iceberg, though. Once these were set, then the real work would begin to implement them. That is what we have been doing for the past several years. and in the end, even though the mission statement is pretty generic, "We are committed to creating a learner-responsive environment that ensures educational excellence and lifelong learning." our steps to create that environment and to foster excellence are on-going and require continual professional development, training and re-focusing on the vision. We do that through branding; simple things like using our new logo on all correspondence and meeting agendas, minutes, etc. and through public relations in many forms from social media to feeding press releases and stories to local print and visual media.
Finally, I really like the summary of the process from the Breaking Ranks II book. They emphasize that the "questions of success will not be based on averages, abstractions or models, but rather on individuals and each student's personal-interest story." This means that the implementation of the mission and the vision must not focus on what is the current hot program or process or on the graduation and test statistics, or the current negative school story in the newspaper, but instead it needs to be about how are we helping James, Melissa, Suzie and Mackenzie to build a desire to learn, graduate and continue learning through a healthy sense of belonging to a a safe and nurturing community.