Myself and many players I know would like a way to quickly and easily assess the performance of our individual fingers on a per beatmap basis.
One way that should be very easy to implement that I can see this happening is by tracking the outcome of your judgement hits on a per lane base rather than as a whole.
This would merely be a convenience and optical feature and is not intended to alter gameplay or scoring in any way.
Imagine being able to mouse over your result screens judgement hits and seeing how many were for which lane similarly to timing deviation and unstable rate.
One way that should be very easy to implement that I can see this happening is by tracking the outcome of your judgement hits on a per lane base rather than as a whole.
This would merely be a convenience and optical feature and is not intended to alter gameplay or scoring in any way.
Imagine being able to mouse over your result screens judgement hits and seeing how many were for which lane similarly to timing deviation and unstable rate.