Drill into lower levels of detail in a matrix, much like a column chart
It would nice to stack row fields in the row box, then allow for a dashboard user to click on a specific row label, to reveal the next level of detail in the table. I.e. I click on sales to see the row labels replaced with now the order numbers. I click on an order number to reveal parts purchased in that order. This way, there is no need to expand the width of the matrix to fit new row levels like you get in pivot.