That could work too. Doesn’t look too complicated. 
Only problem i see is how you would actually fit several pianorolls vertically, even for people with low resolution screens But that’s not up to me to solve. But this could work as well.
On the other hand there’s still some major problems with editing notes in pettern view. (for people who refuse to adopt and use a pianoroll) so I made a quck scetch a while back. This old thread might shed some light to the issue.
Or why not have both? Ctrl+Shift+P Could opnen a vertical pianoroll editor in pattern view. Don’t know why but vertical just makes more sense. since that’s how you see a pianoroll anyways.
Bantai’s scetch is not bad, I would just like to see it tilted 90 degrees clockwize and have it as ONLY a piano roll so the editor buttons on the button would be.
[pattern editor][Piano Roll][Arranger][Instrument editor][sample editor]
or something like that.