Hi Michael, what is it that you are actually looking for? What do you mean a "collaboration platform"? Moodle is a Learning Management System, that is it has a series of tools you can use to present resources to learners, from K through all levels of education into university/college. It is used by White Castle as a training tool, by a Shakespearean company for developing actors, hospitals for doctor and nursing training, throughout business and education where training is required. There are activities and other tools all aimed at assisting students to learn and teachers to teach.
If you want to be able to create single documents and have teams working on them, you can use Moodle and, via the LTI protocols, Google Docs to create common documents. The Moodle story, so far, has few limits, as a learning tool.
Or are you looking for a School Management System? There are a number of alternative, open source projects that may help you here. There is one idea that you may want to consider.
Here is a discussion began by Chris Kenniburg of the Dearborn Public Schools about what he has achieved, and this may be more of what you are after than anything else. While it really supports the use of Moodle, it is clear and really helpful.