Let's imagine each guy at his best. It could be 12 or 15 rounds. Who do you got?
I say AJ was 100% wrong for Kenny Norton, who was always vulnerable against physically bigger, stronger, exceptionally powerful guys who could back him up. Foreman. Shavers. Cooney. Need I say more?
Size definitely plays a role here. AJ's 6'6," 245 lbs, all muscle, quick and powerful. Norton's just 6'3," 215 lbs, and despite being a near ATG heavyweight, never took a really powerful punch very well.
Nothing against Norton, for whom I always had maximum respect. But physically and stylistically, AJ would have been a nightmare.