The usage of RawDescriptor as the default_class in many places in the modulestore brings in an unwanted and unnecessary Mako dependency.
Experiment if something besides RawDescriptor can be used as the default_class in the modulestore.
If removal is possible, do so in the separate modulestore repo here: https://github.com/bmedx/modulestore/tree/master/xmodule
I had good success with unit tests in edx-platform in changing the raw descriptor to not require XMLEditingDescriptor, which was what brought mako in. I've moved and renamed the MakoDescriptorSystem to TemplateDescriptorSystem and removed the mako_module here: https://github.com/bmedx/modulestore/pull/9
This change will require downstream changes to imports in edx-platform if we move forward with the extraction.