When JIRA 3.13 was released we added "shared dashboards and filters". And while that was a step forward, it seems now we need an extra "share permission" that of "editable by others".
The use case is that some one in a team can create (and hence own) the shared dashboard or filter, but others in the team can "edit/improve" the situation by being able to edit the dashboard/filter. This promotes better team integration.
In terms of code change, this is very doable. Currently the dashboard service and search request service check for ownership when deciding if the person can edit a dashboard/filter. It could check also for this new "edit permission" and retain the same interface otherwise.