Show partial grades to figure out where to improve

Most of us will have had a game like the following: you feel like you should have gotten an S+ only to find out you actually only got an A+. Then a lot of players go to the forums to ask what they did wrong. I don't see a downside to letting us know the partial grades (e.g. CS, objectives, kill participation) that make up the overall grade we currently get. Why does it have to be the black box it currently is? Missions could also be added when the partial grades are introduced to the game (e.g. get an S+ on CS and win the game).