It would be useful as a regular user (or superadmin) to be able to set a Dashboard settings (including optionally the period and segment) as read-only.
This would prevent changes to widget position and other settings in context where such dashboards are built for a specific audience (other staff, management, etc.) where any wrong manipulation could accidentally mean unwanted changes difficult or impossible to revert.
Also mentioned here: http://forum.piwik.org/read.php?17,129146
There is a small workaround:
Over the last few months, a few more users have requested the ability to Share a dashboard with someone, and keeping the dashboard synchronised with the original dashboard that is being improved.
This would be useful almost always, for example when one Marketing team member creates the Marketing team dashboard, and wants to share it with others. Currently they need to copy it, but as soon as someone makes an improvement they need to share it back with other. It is not synchronised. So the idea is to build this synchronised dashboard by allowing people to share the dashboard with others and keep it synchronised.