Especially since browsers started to block plugins by default (what a bullshit idea that is, but anyway...) I think WebStart is becoming more important than ever as an option to deploy Java applications, especially JavaFX ones. Nonetheless I couldn't find any reference to it on the JavaFX page nor in the documentation...
I think JavaFX needs to promote WebStart to survive. Few developers even know that Webstart exists, and even less know how it works and where it is documented. JavaFX 1 had great WebStart support, you should do that for JavaFX 2 as well.