Current state (Web 8 Experience Manager): It is already possible to add or remove Embedded Schema fields using the  or  icon. But you can only edit existing fields when they are visible on the website via Inline Editing or by opening the selected component in Form view. If you need to change not visible fields of the Embedded Schema it is not possible to do so via Inline Editing. I would like to avoid that Editors need to use the Open in Form view functionality as far as possible, but the Embedded Schema feature forces Editors to do so. This behaviour is kind of inconsistent as adding and removing Embedded Schema fields is already possible.

Future State: It would be better to have something "gear" button to open the currently selected Embedded Schema fields in an Popup (like the Popup that appear if you click the  icon) where you can edit the contents of the fields.