With the second offering of my Game Industry Survey course, I reworded a few of the homework assignments to make it clearer what I was looking for, based on confusion from the first offering.
Sure enough, the new crop of students is better at providing what I asked for, because my documentation was clearer.
Now I'm starting to wonder if this is entirely positive. In game development, clear specs that leave nothing to the programmers' imaginations is considered a good thing, because you're trying to make a game that's true to the designers' vision. But in a classroom, removing the students' room for creativity teaches them that they should be prepared to accept clean, detailed specs and follow instructions... not exactly the skills I want to pass on to the next generation of game designers.
In a way, if I treat homework assignments as design documents, my students end up getting better grades... but perhaps not learning as much.