I think it would be useful to have the choice to display the accuracy that you would get on a song if you SS'd the rest of it. Basically, your accuracy starts at 100% and only goes down each time you get a hit that isn't a 300 (or a miss).
For example, say a song has 100 notes. You start with accuracy at 100%, get a 300 on the second note and a 100 on the second. With the current accuracy system, your accuracy would go down to ((300 + 100) / 600) *100 = 66.66%. Under the new system, it would go down to ((30,000 - 100) / 30,000) * 100 = 99.67% and stay there until you get another not-300 or you finish the song.
So the difference between the two calculation methods is:
(Total points gained so far) / (Total points possible so far)
vs.
(Total points possible - points lost so far) / (Total points possible)
I feel like this would make it much easier to judge whether or not it's worth continuing a play if you're trying to improve your accuracy or avoid getting a higher-scoring play with lower accuracy.
For example, say a song has 100 notes. You start with accuracy at 100%, get a 300 on the second note and a 100 on the second. With the current accuracy system, your accuracy would go down to ((300 + 100) / 600) *100 = 66.66%. Under the new system, it would go down to ((30,000 - 100) / 30,000) * 100 = 99.67% and stay there until you get another not-300 or you finish the song.
So the difference between the two calculation methods is:
(Total points gained so far) / (Total points possible so far)
vs.
(Total points possible - points lost so far) / (Total points possible)
I feel like this would make it much easier to judge whether or not it's worth continuing a play if you're trying to improve your accuracy or avoid getting a higher-scoring play with lower accuracy.