Excellent suggestions! But I would also propose moving the default-master from /www to packages/acs-subsite/templates/ since it really belongs to acs-subsite. Another idea (since it just came up in a client project) is to move the parameter DefaultFormStyle to acs-subsite to be able to not only change the master-template on a subsite-level, but also the form-templates, which would make more sense from my point of view.
