It would be nice to have a "Stacked Area Chart" option where each area is plotted not over the previous category, but stacked above it. This kind of chart can be useful to show how a breakdown of some category variable changes in time.
The same feature can also improve usability of Output by Hour by Type and other similar chart templates. At the moment, depending on the order of variables, some area plots may be hidden (orange area is behind the blue one):