I think it would be very useful if there was some kind of indicator to display what our current letter grade is in quests (you know the one that's like Sonic games and displays D,C,B,A, or S at the end of the quest). We can only guess how good we are doing in a quest before getting the letter results, so for expeditions for example, people will kill most of the enemies they run into to get an S rank, because it's easier than someone having to figure out the exact amount of enemies we must kill in these areas to get an S rank (and heck we don't know if each enemy has a different value to the grade like they do in the ecological survey quests).
I feel like we should have always been able to see what our current letter grade is before the end of the quest, so we don't have to use more time than necessary completing a quest for a client order, or just to farm a boss' drops. This should be easy to implement, as the game already keeps track of this, all it would take is making it displayable somewhere, heck even having the system send us a message in the chat as our letter grade increases or decreases could work if adding a separate indicator isn't possible.
I think this would be helpful to everyone and easy to implement, so I don't see any reason for this not to be added.