Like many things in software, it is always hard to discuss “things” without specific examples. The size or scope of the discussion has to match the circumstances. Design and “vision” for a single functin/feature is radically different than the design or vision of a “change the game” product. Timeframe can often be important… are we talking about year-long projects with 20 people? or decade-long projects with 2000 people? at any rate, even the latter can be broken down into small chunks of reasonably-sized sub-projects and shorter deliverables. in other words, in some sense, ideas about the role vision plays are/should be scalable…
do you find product owners have vision that spill beyond the purpose and needs of the system into disciplines like usability? architecture? maintainability? extensibility?
my experience has been one of working closely to collaborate as a partner with product owners or the “customer(s)” to blend their wants and desires into aspects of software design and usability that can then be conveyed to the team as a “vision.” the phrase “two heads are better than one” comes to mind.
setting the vision, conveying it to the team, allowing good ideas from any quarter, at any level in the project, at any time; but also staunchly defending the vision as needed. contradictory? maybe, but not really.
As far as the team and others peripherally involved grokking the vision… yeah, it requires constant repetition. “If I had a nickel for every time…” I write or speak the vision… I say it in scrums often. It is all over the wiki, whether you start from the “project vision/overview” pages, the FAQ pages, or the page titled ” Grokking
The wiki is also a very useful place where i keep discussions, brainstorming, etc. New people come onto the project and may have “a great new idea” — like the other 5 before. So a gentle discussion and a wiki link can direct them to a wealth of corporate memory and explain why we may have considered that “great idea,” but chose a different path instead.
nonetheless, it is no small feat to carry a torch of a vision… requires continuous championing, occasional foot stomping, and lots of repetition, in my humble experience.