This idea sounds like a good one. Allowing students to see a correct class diagram example that can allow interactive explanations seems like it would be great. Interactive explanations in fact generally appear to be good ideas, tying the OMT idea to interactive illustrations and the like. At the same time, it's interesting how the author pointed out that students thought this system would be useful for documentation as well. Sort of funny with javadoc (a way to generate html documentation for java code, used by wave) now being used. I see that type of tool as being very helpful as well.

Unfortunately, I don't have much else to say :(