In Google Classroom I can switch over to the Student Work view and can see their work "in progress." I see a thumbnail sketch of every students' assignment and can quickly see who is not very far. I can directly open the document from this view to write comments directly on the Google doc. This creates a very immediate, organic interchange between teacher and student.
It would be great to have this same feature in Canvas for those assignments that are works-in-progress so I can monitor them while they're working and provide immediate feedback prior to them submitting their paper.