FTP is insecure and SFTP is not practical in many situations due to the need to manage accounts. Collaboration Edition is known to have many shortcomings, and the use of FTP/SFTP is the most awkward of them.
Consider integrating with modern file sharing platforms that use secure RESTful web services to handle file transfer and file sharing. An organisation member creates a dedicated path in Dropbox or OneDrive, for example. This user has the authority to manage this path, who can read from it and write to it, and who can share resources within the path. They can also define the rules regarding the the method of sharing resources, such as: by configured user, by sub-directory, or by whoever has a unique URL for a path or resource.
Instead of pushing and pulling TBUs and updates to an FTP/SFTP server, Passolo uses an SDL or user generated integration with one or more of these file sharing services. It could upload a resource and request a unique URL from the service. The URL is then communicated to the appropriate parties.
Allowing SDL Community developers to create their own integrations will help to pull Passolo into the rapidly advancing world of integrations and micro services. This was the emphasis behind a talk I gave at LocWorld 33 in Shenzhen on continuous localisation, and it was very much welcomed by the audience as a way of making sure localisation enhancement tools keep up with modern technology.