Feature request: Flattened row headers, mass expand/collapse hierarchy

See picture for reference.
I have a need that could be described two different ways (or maybe it is two different needs).  I would like for there to be a way to flatten row hierarchies similar to the flat form layout option but only applying to the row headers.  A visual example from Tableau is here
https://onlinehelp.tableau.com/current/pro/desktop/en-us/buildmanual_dragging.html?tocpath=Design%20Views%20and%20Analyze%20Data%7CBuild%20and%20Explore%20Data%20Views%7CAdd%20Fields%20to%20the%20View%7C_____0#Rearrange
I know that OLAP cubes are not designed to display flat table data in this way, but the performance of your component is so good you don't seem to have a problem dealing with it.  By supporting it solves other reporting needs.  It really becomes a user experience pain to click expand on every row to make the nested data display.  Ideally there is a view option that flattens this data out similar to flat form, but then I find myself often wanting to expand an entire hierarchy level and not wanting to click on each row to do it.  A right click on row header menu option to expand all / collapse all could possibly meet both needs.