The previous version (v2) is 5 star, but v3 is missing key features! I hope the features from v2 are going to make it into v3 at some point. Also, not a fan of the new UI in v3!
I wish Mozilla hadn't decided to kill off 'legacy' add-ons before WebExtensions had become a good enough replacement!
Yes, we definitely plan to add functionality back, but that will take time. We already waited with publishing this update as long as possible - Firefox 57 will be released in merely a week.
