You could say that The Wave did more good than bad in that it enabled the students to learn what life was really like under a fascist regime. History books can tell us a lot about the past, but the kind of experience offered up by The Wave can provide an even deeper insight into how extreme ideologies work and how they take hold of an entire population and make them do terrible things they ordinarily wouldn't dream of.
The Wave has made the students think more carefully about what they believe in and why. It has encouraged them to be more questioning of group rules and values. Even after The Wave experiment is abandoned, the students will still find that school life revolves around groups of one sort or another. From now on, most students—certainly the more thoughtful ones, at any rate—will be much more cautious about the groups that they will join and start to be more independent in the choices they make.