I am looking for a high level scene graph language for web delivery of interactive simulation content to mobiles. Something that can be made to map well into openGL ES 2 API. I have been thinking an XML based language would be right for this, but it would have to be very cut down, much like ES/ ES 2.0 was cut down from GL but is still a powerful API.
The two main royalty free, open standards XML languages that I first thought of, Collada and X3D, seem too large or encumbered with "dead wood" much like OpenGL was considered for mobile graphics. Maybe KML is another choice.
If there is no language that fits the bill, what do you think would be the best language to start with and make a profile for mobils? My initial thinking is that X3D, being designed for web interactive content delivery, would be the best place to start. But Collada has become very popular and I don't know enough to judge if it is a better starting point.