A few suggestions regarding linked parts
Allow for a single staff to link to multiple parts with the same notes, but different transpositions. The most common use would be to have Treble Clef and Bass Clef Euphonium parts generated from a single Euphonium staff on the score, but there are other uses as well (optional Eb/Bb Horn parts from an F Horn staff, Treble Clef and Bass Clef Trombone/Tuba parts for British brass band literature). I'm aware you can just create another staff and set it to invisible on the score, but this would avoid errors from copying/pasting to the alternate parts when editing the score.
This is a bit more of an edge case, but allow for saving/loading styles and page settings to multiple (but not all) parts at once. For example, in an ensemble I'm in, some players prefer portrait-sized parts and others prefer lyre-sized parts. I have a linked portrait part and lyre part for each instrument, but if I want to make consistent style changes to just the portrait or landscape parts, I have to toggle into each part and select Style -> Load Style for every part. It would be incredibly helpful to be able to mass load styles from the Parts window.