I read three major points: Ownership, curation, and diversity. As the latter two, I feel, require hands-on experience, I'll focus on the first.
For Ownership, the author / OP appear to suggest that content ownership is about where the content is hosted. From the article (again, never heard of the service before now), it seems that preserving redirects and letting you create whatever URIs you want, and therefore move / control content, would suffice. Am I just missing something?