In my MA (three hours per week) we spent the first half either with a guest speaker or looking at specific topics. However, I thought it was badly planned and knew the lecturer was winging it. I would have liked that half of the lesson to cover eg dialogue, plot, characterisation etc and for us to have had a week to come up with good examples and read the theory books relating to that topic.
In the second half we were split into groups of about five and did workshops whereby two people's work was discussed each week. We were given the work the week before (if we were lucky - some were dreadful with regard to that) and critiqued one person's and then the next.
One way around people not having work ready is to say that if someone else has their work with them all ready for the group, then that should be read instead - I don't think they'd be late, then.