I think when he got to the Habs, there was nothing left of McKay. He was the prototypical Devils player. Tough, mean, played the system to perfection. However, his last 1-2 years, his play really dropped off. My last memory of McKay in a Devils uni, was Domi absolutely beating the crap out of him. (during the game where McKenzie jumped Domi b/c of the Nied elbow).
I was wondering about McKay as well. I can easily see him coming back in some sort of office/scouting position with the Devils. Maybe like a hybrid of what MacLean and Dano do. Who knows, Lou seems to be very loyal to guys like McKay, so it wouldn't surprise me to see him back in a few years time.