I have the same request: Sankey charts are a must for a lot of applications (i.e. for energy consumption or money flow visualization).
Being central to my future application, they are stopping the adoption of FusionChart :-(
As not so many chart libraries provide Sankey Charts, they would give yours an extra kick.
Even simple ones like in Google Charts Sankey are enough, but please don't lose time with extra features such as shaded colors on flows, or pointing arrows.
If you can provide at least in the beginning a quick & dirt Sankey, it would be great.
Waiting for them.