1) I've changed the color of the on state icon from white to dark red to represent its state better. Uploaded the new version, should update soon.

2) I have no time resource currently for a preferences panel.

2.b) Edit.: I've made some recent improvements and in version 1.4 you can use the Sync feature of Firefox so you won't need to do tiresome exports and imports of data but instead you can sync the settings to all your devices.