Glissando needs an improvement. When one adds a glissando to a note w/o a goal-note playback wont play the glissando. So a fall or gliss-down wont work.
It also would be great to set the startpoint and duration of a glissando.
When a glissando is added to a whole-note the duration of the glissando covers the complete note-duration, even when the gliss should be played at the very end of a note.