Currently the Dashboard functionality allows you to filter by Workspace. We have a number of use cases where there is a need to filter the reports/panels within the dashboard by additional fields. For example, we have dashboard that apply to initiatives, but our stakeholders typically care about one initiative at a time, so in order for us to meet their need, we end up creating a copy of the dashboard for every initiative they have - not very manageable.
Recommendation is in the Dashboard provide functionality to identify common objects within the reports in the dashboard panels, and provide the ability to add a filter that applies to all of the panels/reports within the same dashboard. That would be a huge time saver.
As a possible interim solution to the above is to include in each of the panels the ability to filter on each of the reports within the panels, so although they would need to filter each report separately, at least they have that ability.