I am not sure if i should add my “Brainstorm” Output and some positive shouts for some ideas, but here it comes:
I miss some realy easy and simple features in Piano Roll like this:
- mirror / flip selected notes hoizontal and vertical (flipping adds a whole new world in melodic design), today we can just reverse it or scale in so many options
Positive Shouts (for some features i already voted 
):
- these chord idea in the feature request is just awesome, if this can be changed per bar or similar time sigantures, so you can create chord progressions easy, by presetting a chord progression draft. Okay sure you can use the Diatonic Transposer and automate the chords as well, but u will missing the information in the automation lane in wich key you are…you need to open the plugin…
→ Select / highlight the scale to work with on the piano roll - this one is pretty cool, prevent switch to the pen tool, or using shortcut (yeah maybe shortcuts is a bit faster than clicking but) if we have selected area handles we can maybe have an option also for shortcuts to tilt orincrease dynamics:
→ Better piano roll - #3 by ultratot
I realy hope that will be an addition for a feature request