Debates

How can we best use blended learning for debates?  Up to now, my students have all done individual sheets with three arguments for the affirmative, three for the negative, and counters to each argument. I want to maximize individual effort and work, rather than letting a couple of students do all of the work for each team.  On the other hand, it would be good to have each team work on the best arguments for their team.  Any suggestions?