It was really rough in the beginning - bad and buggy UI, settings did not seem to persist, etc. but at least since 10.1.5.1, it's looking good. I wish there were clear directions, but the developer did give some suggestions in a response or two below that basically clarified everything: click the naked "S" to mark something as "trusted." You will notice a clock icon to the right of the "S" which means that it's temporary. Click the clock again to make it go away and make the "trusted" status permanent. Then there is the "untrusted" button and the "custom" button. The custom button allows you to choose what elements are allowed.

Knowing how to use the 2 buttons, the "trusted" and "untrusted," and the temporary button should help clarify this extension's usage and make it usable again to everyone. I wish the rollout had been smoother from the beginning, but I encourage everyone to give NoScript another look. Also, I hope everyone understands what a monumental change FF57 has brought about in terms of extension development and that extensions like these that do so much behind the scenes have been made extremely difficult to maintain.