When creating a stacked bar/column, the end user must consult the legend to know which portion of the stacked bar. This can be cumbersome if there are a number of categories in the legend. And even worse when the colors in the legend are not distinguished enough.

A feature that made it easier to add category labels to the data labels would make this easier. Although it's technically possible to add category labels using annotations, doing so requires constructing a very customized R Table.