it would be great to exclude well-known items like sp_server_diagnostics in an AlwaysOn deployment (either preconfigured and user defined exclusions like in SQLdm). They skew up the charts and the message of the dashboard.
Our database developers often complain and ask about this: What it is? Why is it consuming so much time? What can they do?
We have to explain them to ignore it. But even everybody ignores it, it skews the charts due to its long bar compared to real data collected.