This is a list of features that have/have not been integrated in SceneBuilder
As I said in the past, my dream on the subject is one day to make a super better alternative to SceneBuilder.
Unfortunately, until that day comes, I'll have to stick to what we have.
Integrated
SceneBuilder detection system
Theme Support. Partial at the moment since the theme API is in development
Not Integrated
Ability to customize ripple generators (can still be done via CSS)
Ability to set icons in controls that support it (e.g. FABs, can be done programmatically in the FXML)
Ability to set variants (it can be done by adding the variant' style class in the properties inspector)