Halve/double time values, or better
MS truly needs a feature to halve or double all the note and rest values in a region. While the most obvious application of this might seem to be "a slight boon for writers of prolation canons", a perhaps better one is to correct imported music (be it MIDI or something better) whose author "customized" the note values to his or her taste, such as the eighth-note pulse of that Sarabande we just discussed, which Bach wrote as sixteenth-notes.
Multiplication/division by other than powers of 2 (e.g. 3) is conceivable.