Having a clear vision makes thing easy for the entire team to make the right decisions at the right time.  Being aligned on what that vision means therefore is extremely important to ensure a team is fully and properly empowered to drive the business forward.
The process of developing or validating the vision includes:

Understanding the reasons and goals for the offering in question
Perform ambiguity reviews to find where there are incongruities within the various perspectives
Work with the team to create an aligned and singular vision that the team can own
Document and define a high level roadmap