I know people have discussed solutions in the past (eg here) but I haven’t seen anything quite like my idea:
There is also an on-going discussion for piano roll that you should check out:
https://forum.renoise.com/t/brainstorming-piano-roll/12547
Look at the date on that first post. It’s a good thing that you plan on sticking around, as you say, “many years” 
I like the interface mock-up though. I think this would be what I’d go for ideally too.
Another thing to add: highlighting a note with the cursor should highlight the corresponding piano roll note.
I’m always getting confused with my 4 or 5 note block chords. Sometimes I have to switch to the instrument view just to understand what’s being played!