I don't think jwz would have had a problem with it if you called it EmbeddedGL or PhoneGL instead of trading on the name of OpenGL. Like jwz I thought "Oh its OpenGL I've got code already that does most of what I want." only to find none of that code worked.
Nearly all design is incremental. That's how design works. That's partly why chairs are still recognizably chairs, and other useful stuff like that.