So why would this be interesting for HN readers? The idea isn't that revolutionary, and there is no code and no way for people to do much.
To show what you can do with AngularJS directives and that combining it with D3.js it can be quite powerful (even without source code). Anybody who worked with D3.js, should know how much boilerplate code needs to be written to have a visualisation. By abstracting that code in directives, it allows users to use out-of-the-box d3.js graphs. Someone could go ever further to implement an "interface" to customize these graphs through angularjs.
To anyone who's interested: I replied to another comment with a tutorial blog of how to create d3.js directives