Rather than investing resources in developing yet another 3D framework in JavaFX, I would rather see the time invested in integrating the WebView into WebGL.  This seems to be a much less daunting task than creating a framework from scratch.

Additionally, this would follow the existing paradigm of embracing web standards and bring fairly mature frameworks such as Three.js into the JavaFX fold.  There is an immense amount of existing content that could then be seamlessly integrated into the JavaFX experiience.