Legend Value Text Customization

Adding customization to the legend values would be immensely helpful. In most charts, I am able to adjust the legend values by renaming them, but this only works if the field is under the x or y axis. However, if I add a field to the legend area, I do not have capability to customize the text so that the chart is more user friendly. Currently, the only way to go around that from what I've seen is to create either a switch function to rename the values, or create a calculated column and rename to what I want displayed. However, doing so I would assume impacts performance. If there was a more straightforward way to edit the text values under the visual pane in the legend field, that would be really helpful. Thank you!