Changing various part properties mid-score.
It would be rather nice if one were able to alter a number of part properties mid-score. These might include printed matter such as the short instrument name (text to the left of the score) and the transposition (although I do understand this to be included in the coming update) as well as playback matter (sounded instrument, reverb, etc.). In lilypond, one simply alters these variables mid-score and the change takes effect. It would be useful if something like the Instrument text element could also alter these as one of its properties.
P.S. Number of staves per part would be the single most useful thing for this to be applied to. If I could add or remove the number of staves each part is allotted and have the change take effect on the next system, it would remove an incredible amount of unnecessary score manipulation. For a suitable example of where this might be applied click here.