Georgia Tech's OMSCS program addresses these issues very well in my experience (I'm finishing my 3rd and final year). Assignments and exams follow strict schedules, student collaboration is very strong (via Piazza, Slack, Google Hangouts), each student receives a grade, and the cost is cheap but not trivial (i.e. there is a financial incentive to make the most of the class.) I am very happy with the program and feel it should serve as a model for other institutions who want to offer MOOC like degree programs.