I would like Canvas to allow instructors to opt into storing the written answers of all students for essay answers to questions on quizzes and tests. Canvas would then search all new answers in a database much like Turn-it-in.com does with full essays to generate an originality report.
A limited version of this would limit this discovery to a particular instructors current and past courses, though a more robust version could compare essay answers between all students.
Such safeguards against cheating are becoming more and more essential to maintaining a functional online education program. Catching cheating also helps prevent financial aid fraud.
This is a more complex feature to add, but I feel it is vital.