There are a lot of IDEs out there and most of them do some things better than Atom, but the one thing that Atom does better than all of the rest is makes packages a first class citizen, and makes developing a package as easy as possible. Atom is the ultimate IDE for people who want to customize the IDE to do exactly what they want.
Being that package development and customization is such a pivotal part of Atom’s success, I believe that documentation on how to develop packages and use Atom’s features should be a top priority. I have stated this before in other discussions topics.
It would be great if the Atom developers could follow the principals of Documentation Driven Development. Start with the documentation to ensure that each feature is well documented and as a self check to see if a feature is worth developing.