Pan settings for individual notes
I think a nice addition would be the ability to set the panoramic position of individual notes. That way I could create a drumset with, say, the hi-hat on the right, ride on the left, and bass in the center. While it could be some sort of drumset setting, having it be a property of the note (able to be set in the Inspector panel) would make it more versatile. Perhaps the setting could be a number from -90 to 90 (as in degrees) or it could just copy the knob from the mixer. Changing the pan position of all instances of a single note (or drum sound) would be a matter of simply selecting the entire staff, right-clicking and clicking "Select-->More-->Same note (in selection)" and then changing the value in the inspector panel, like you would do for velocity.