A work around for the #1 requested feature.
According to Google, the most frequently requested feature for Classroom is the ability to setup a class with multiple teachers. It looks like this functionality will be built into a future release, but currently this capability is not supported. In the interim, use this work around to let another teacher open and edit student assignments. The 90 Second Tech tip below explains how you can leverage the powerful collaboration features in Google Drive to share your Classroom content with another teacher.