hm…
another idea:
An option (dialog) to play several arrangement (e.g. verse, chorus, intro, bridge …) in an definable way and to merge them into another arrangement in a definable way would do the trick also.
This would be a very good feature to compose songs.
In Cubase this is done by mark portions of the tracks (by times) and by having a dialog to bring these portions in some order. Then you can play them and merge these portions in another project.