WP gives people the illusion of content; they don’t actually have to have anything to say as long as they have a fancy theme and a big ol’ slider. Flat-file systems make sense for people who want to focus on content and content alone (WP can do this, too), whereas WP has become a fully-featured CMS.
This reminds me of the people who mistakenly claim designers are so dumb they think they need a Mac to work, when the simpler truth is that most designers like well-designed things1. So I’m sorry, but the above quote is horseshit. Bad content is bad content, and no fancy slider will hide that. Nor does the underlying CMS have anything to do with a blogger’s ability to write, unless it’s so opaque as to be unusable.
Which brings us to the trend du jour: flat file CMSes. While they’re all the rage with developers, I seriously doubt they’ll get much traction with anyone else until they become simpler to use. At the moment, they’re certainly anything but. It comes as no shock that they’re very clearly by developers, for developers. (Mysteriously, the simpler ones also tend to be paid solutions.)
No-one’s denying that Wordpress has become one big-ass chunk of code, but your average blogger doesn’t care – he or she needs a tool that’s reasonably easy to use. Logging in to Wordpress, clicking “add new post” and writing in the easily fathomable composer is simple. Having to learn markdown and some obscure PHP templating engine is, y’know, less so.
Something’s bound to dislodge Wordpress at some point, but it probably won’t be Ghost and it certainly won’t be something you run from the command line after installing various ruby gems or whatever the fuck.
1 Not claiming all designers prefer Macs, by the way.