I'm thinking of exporting all of the game objects and their components into a JSON file format.
JSON is one way to go. In fact, it's exactly what we are using at work for our research framework.
We chose JSON because it is human readable. We don't store actual models there - just model filenames with relevant data (position/rotation/scaling). We also store light source information, camera definitions and some other parameters.
The main drawback is that parsing text files is slow. If you plan to store actual model data there (i.e. vertices), I would advise you to come up with a binary format. It will make a huge difference in loading time when loading a scene with large amount of vertices.