Actually, if you look at this article you'll see that it did need expanding, and the student's edits were mostly an improvement. There were a few issues with sourcing our synthesis, but nothing major.
In my opinion we need to get more people like this involved in editing, rather than pushing them away. There are lots of articles that need help, and it's a great learning experience.
It is supposed to be the repository of human knowledge.
Not the quality such that a student 'learning' about a subject can do an assignment of editing it.
When this student has long gone, it's the Wikipedians who have to clean up the mess.
What real Wikipedians do is clean up vandalism, correct spelling and grammar, arbitrate differences of opinion.
They don't just sit around creating content then leave.
If you really want to help Wiki, work on teaching students the politics and how to do the real work that's needed to make it so great.