"Direct Access" which unfortunately only works for domain joined clients (I dont get it why u made this fantastic technology computer based and not also user based which would also work for non domain joined computers)

Giving customers access to our fileshares via https would be easy then.
Currently almost all products from Microsoft are ready to deploy to external users via https the only thing left is classic filesharing.

I know u want customers to use ur cloud services, but there are also a lot of companys which could not use them for compliance reasons, so please dont forget your on premise product line.