The libraries are a fantastic aspect of the Arduino and the key thing that makes it a worthwhile if otherwise rather flawed platform. It took me a long time to warm up to Arduino but I love the way I can grab some widget and very often grab a library with example code to make it do something right away. It provides a great way to test the thing out and explore its capabilities right off the bat. I'd love to see a similar collection of HDL modules form, blocks of code that do the grunt work like initializing the device and communicating via whatever interface it uses and bring the controls out to sensible interfaces that can be tied into other modules in the top level file. Ideally these modules should be well commented, especially at the top level explaining what all the inputs and outputs do and what sort of signals they expect.