With the Add Data widget, I would like to see the option to change the symbology of the layer that is created when adding data using the Add Data widget. I've built an EB app that allows people to make their own geoPDFs for use in the field while doing groundtruthing. These maps typically include a raster of canopy height or perhaps an aerial photo. If someone adds a shapefile or KML file of polygons, those polygons will have a fill by default which will obscure the raster information that is important.
At the very least, I would like options to change polygons from solid to transparent fills as well as changing the color of polygon outlines.