Is medium trying to compete with wordpress? Maybe the simplicity is its beauty. Not many people care for all the bells and whistles that you can dig into with wordpress.
I agree that if you're thinking about analytics, etc then you've probably outgrown these simple platforms. In this case you should definitely consider running your own install because now it's your business, and not just a journal.
Ugh, that looked good until I got to the bit about using Markdown. I'm not using a vt100 terminal, for gods sake, I can handle an editing system that understands basic formatting.
I agree that if you're thinking about analytics, etc then you've probably outgrown these simple platforms. In this case you should definitely consider running your own install because now it's your business, and not just a journal.