Just for fun - it would be neat to track certain stats for each character. I think I would be most interested in: - # of SP kills - # of SP deaths - # of SP encounters - SP survival rate (Of course, this might work better as a 3rd-party data site. The API would need to export individual character health + kills, and probably provide a way to filter character data by player.)
The API probably doesn't support this ATM (like, kills/deaths for a given character don't seem to be in the dox), but it'd be pretty sweet if it did. If BM is going to export detailed battle history, though, I'd rather see replays before this. Either way it's a neat idea