It would be cool if the echonest API would also return a waveform (in JSON form preferably to allow custom styling) for a track. I'm not sure why this isn't a feature yet considering the synchstring feature but I can see this being very useful for everyone that wants to display the full waveform without having to have the whole audio data on disk beforehand (for example in a streaming environment).
There is already an opensource library that produces such json files from .wav files: https://github.com/liufengyun/waveformjson
It would be great if you'd consider adding this to your lineup of already awesome features.
