I like your suggestions. They would certainly change the business model of the platform. One thing I like about Vocal is that they check for plagiarism and have an editing team viewing your work as soon as you hit publish. New Writers on Medium are left to meander around aimlessly to get published. I like your idea of a graduated system. Having volunteer publishers is not sustainable long term IMO.

On a related note there is an accusation of plagiarism from a writer published on Our Human Family pertaining to a Medium owned publication. That will be telling.