Multiple parts same line
It would be good if you could get 2 (or more parts) based on the same score part but with the ability to set the transposition and clef independently on the parts. For example having a score part for trombone written in concert pitch and bass/tenor clef but having the ability to create a standard part for trombone in bass/tenor clef and concert pitch, but also the same part available in treble clef Bb for brass band trombonists. Similarly French/Tenor Horn part variants in F/Eb transpositions. Changes in either part/score correctly propagate across the others.