As a start, I'd like to get this information in response to a PGN I submit. It could allow me to create an app that tracks accuracy over time (or perhaps even by opening).
Next, I'd like to get a PGN returned with annotation symbols for each move. Possibly some annotation that includes best moves (when there is an inaccuracy, mistake or blunder).
The coaches end-game comments are also useful.
I also find the game classification useful so I can track results based on this. For example, which openings or defenses am I strongest with? Which ones do I need more practice with?
I really like the game review feature at chess.com. I would be very interested if there is an API that allows me to submit a PGN for a game and to receive game review response.
Any plans for this? It could allow Chess GUIs to integrate with chess.com.