I think this is a good idea. I've thought about doing something like this for books as well. I haven't yet thought about doing this for programming languages or frameworks, but maybe I should.
Well, some of the courses will have large overlaps.
You might have 5 different courses teaching "intro to python".
Also, if a study group successfully finished an intro course, they might want to take an advanced course together. Or do some non-MOOC advanced learning.
After all, people aren't taking courses in a vacuum. They're taking them as part of a learning path. That path can include additional courses, exercises, projects, and a lot more.
Say I want to learn a new language or framework. It would be nice to be able to find a group of people learning the same thing.