No news. We still want to improve the Box2D support, but other things have been given higher priority.
We do also plan to move Box2D and Bullet into native extensions. That way developers can fork and expose more parts of the API (although without nice editor bindings).
For now, an alternative would be to use your own physics extension. I started a Chipmunk2D extension a while back, but it’s not finished yet:
Forum post: Box2d update
HTML5 demo: https://britzl.github.io/Chipmunk2D
Note that this extension doesn’t give you any editor integration so you need to set things up via code. I wonder if there’s some external tool to create complex physics objects with bodies, joints, springs etc?
What kind of joints would you say are the most important to implement first?