Encouraging students in large sections to write is a challenge.
I use the graded survey feature for this, and I grade mainly on word count for the open-ended questions - then download that data into Excel for calculating word counts and sorting based on that.
I would love to see a feature in Canvas, possibly with the graded surveys what tracks word count in survey responses. Ideally, if the instructor could set up some rules for the scores that would go into the grade book Canvas based on the total number of words, that would be amazing. (300-400 words = 50% of the points, 401-500 words = 75%, etc.) Or even, like Yellowdig, if it didn't accept the survey response unless it's a certain number of words - even that would be good.
I'd love to know if there is any other way in Canvas for students to write short essays (in response to specific prompts) with some sort of automatic grading features.