It'd be great having the option of configuring the Anonymous user dashboard via the Admin panel, so when an anonymous user accesses Piwik, the dashboard is shown as the admin wants.
you can change the dashboard by editing plugins/Dashboard/index.tpl and change the string
piwik.dashboardLayout = 'VisitsSummary.getLastVisitsGraph~VisitorInterest.getNumberOfVisitsPerVisitDuration~UserSettings.getBrowser|Referers.getKeywords|Referers.getSearchEngines~VisitTime.getVisitInformationPerServerTime~ExamplePlugin.feedburner|'
There could be a GUI to do this configuration automatically.
Note, this can now be changed in the /plugins/Dashboard/Controller.php look for the function called getDefaultLayout()
This feature was added in #3011. You can define the anonymous dashboard by setting the default dashboard layout.