We've done articles as well on the main site. Anything coming from a dev twitter is them discussing things they are interested in or they think the people that follow them might be interested in. None of it replaces any of the official blog things we do. The reality is that this kind of design insight comes usually late at night, off-hours, in the free time of developers that feel like they have interesting things to share. We'd rather empower the people that work on the game to do that when they can, rather than restrict any communication to official blog posts.