It would be great if clicking “Edit Source” could open the symbol in a new Sketch window (where you can’t switch artboards and and dont have access to components, you can only edit the selected symbol) and that way you’re editing your symbol right next to the screen containing the symbol and you can see in real-time how your changes to the symbol impact the screen using it.
Only way I found to do something like this is to bring the symbol right next to the screen using it, but that’s not very flexible and is a lot of setup work every time.