A good example of where a product's market is limited by it's branding. I can look his points and see that they're a CMS's features, but in my head I'm thinking "WYSIWYG blog entry, adding pages to a blog, blog, blog, blog".
The reason it should branch out into being a fully-fledged CMS is exactly as the author describes: usability. It's so much easier for users than most other CMS's. Despite other deficiencies, that is huge.