Do you think that it would be a good idea to introduce a new file format (.j3s ?) for the SceneComposer. From what I understood from the core developers j3o is only meant to be an intermediate format. It can change with new versions of the engine. I have/had some problems with j3o (now/past) and the SceneComposer.
I mean issues like in this thread:
Jmonkey 3.1 scene editor static rigid body control error?