Gray-out empty slicer items
When data is filtered, slicer items that represent no data should be grayed out (or otherwise indicate this) - similar to the behavior of slicers in Excel.
This would help the user to see which slicer categories actually contribute data to the report.
Agree. Having inapplicable slicers just disappear is confusing.
Agreed. Again this is an area where Excel exceeds Power BI in what it offers.
I often need to explain why we should use Power BI and not Excel. Feature parity in areas like this would help me make the case for Power BI. My users aren't going to be happy with slicers in Power BI that reduce their ability to analyze data effectively.