Squeak;

At one time I used a Roland EM-2000 arranger with a Kurzweil PC88mx because I couldn't stand playing the EM's 61-note keyboard. And I managed to remotely start/stop and do various things but it was a lot easier to perform when I got an all-in-one arranger in the Yamaha 9000 Pro.

My 9000 Pro has 11 buttons dedicated to selecting the various arranger verse/chorus/fill/variation options alone, not counting the usual start, stop and tempo stuff. I suppose those could be assigned to a controller but you'd have to do some homework. And then you'll want to remember how to recall all those settings on the fly on a dimly lit stage while playing... not a job I'd want but certainly not out of the question either. I'd still take an all-in-one arranger over a controller and arranger combo.