I often work with copies of one feature layer, but display different information via the symbology. Changing the pop up information one by one for each layer is tiring and time consuming. It would be nice to have the option to batch-change pop ups for a certain amount of your layers in a map in ArcGIS Online. It can be as easy as adding a drop down menu in the "change pop up" window to import the pop up information from another layer.
I would highly appreciate the implementation of such a feature in ArcGIS Online!