It would be great to have a way in the app (I presume JOSM can do it already) to duplicate an existing route so it could be modified, as there are often very similar routes (i.e. a few stops skipped on weekends) that are painful to create in the app now.
Yup, that's something I want work on for sure. When saving a route, you can alternatively choose to save it as a new relation and automatically connect with a route_master of your choice.
It would be great to have a way in the app (I presume JOSM can do it already) to duplicate an existing route so it could be modified, as there are often very similar routes (i.e. a few stops skipped on weekends) that are painful to create in the app now.