Imagine an arrangement of a hymn for a church choir with orchestra, in which the women sing the first verse, the men sing the second verse, and they combine on the third verse.  On all three verses, the tuba part is identical.  Currently, if I hear something that I want to change in the tuba part, I have to manually find it and change it in each of the three verses.  It can be very easy to miss something.

I would be interested in an idea that I would call Master/Reference.  I want to select a block of measures for one or more selected instruments, mark them as a "Master" block, assign a name to that block, and also be able to assign a notehead color to all notes in that block. 

Then, I would like to move to another point in the composition and create a "Reference" to that "Master" block.  For example, if I have defined a Master block consisting of measures 17-32 in the Tuba line, I could (perhaps) right-click on measure 49, select "Insert Master Block Reference", and then select that named Master block, whereupon measures 49-64 in the tuba part would immediately look like measures 17-32.  Reference measures could also have their own notehead color, or perhaps a shaded background, to indicated their protected nature, because Reference measures should not respond to any direct note change requests.  Instead, they would always take their contents from their Master block.  Changes to the Master block would immediately be reflected throughout the entire composition. (I'm ambivalent about whether music spacing [Ctrl+4] within Reference measures could be adjusted independently of the spacing in their Master measures.)