Haney is one of my top 3 favorite bb's, and I will say that Haney's peak condition will not compare to Coleman at his best. And even if Haney would have taken the same drugs and amounts that Coleman did, he still probably would not match Coleman's totall package around 1998.
But we don't really know. Haney had maybe a better chest anyway. His torso had potential to be as big as Coleman's, and maybe with a slightly slimmer waist. And his calves were better, but Haney's arm would have never matched Coleman's, no matter what drugs he was on.
During Haney's era, bb's still mostly trained on 3 day splits, 6 days a week, hitting every body part twice a week. and they were on far less drugs than today, where most current bodybuilders train each bodypart once a week. As far as his torso was concerned, this training didn't hinder Haney. But maybe for smaller muscle groups like bi's and tri's, this workload was too much. Not only were arms hit directly twice a week, but also getting worked when he did chest, back and shoulders. Now, like I already stated, Haney didn't have the genetics for arms like Coleman, but maybe if he had trained in a more modern manner, with a more modern drug regimen, than they might have been much better. when he was younger, Haney said he built most of his mass training only 4 day a week, but he still hit everything twice a week.
Now one could say this theory is way off, since Haney's legs were small, and legs are a big muscle group like chest, back and shoulders. But like already stated in this thread, almost no one had huge legs back then. Haney's were good enough to win, so why bust his ass to get bigger. I think on a whole, bodybuilders didn't squat anywhere near as much weight as they do now. I am sure on average, today's bb's are stronger all around, but especially so in the legs.
I think when you compare bodybuilders or athletes from different era's, it is more fair to compare how they did against everyone else of their time period. Both Haney and Coleman were able to beat everyone else using comparable drug and training programs, so both are great.
If Haney would have been born later, and turned pro in the mid to late 90's, instead of 1983, his physique would have blown away the real Haney package that we are discussing in this thread. Would he have been as good as Coleman?
Probably not. But we don't know for sure. Just like we don't know how Coleman would have looked, if his prime years were during the 1980's.
But I will say that I do know both of them would have been great. If you can dominate an era, you would have been near the top at least, no matter when you competed. Especially from the 80's on. After the popularity of Pumping Iron, and then his turning that into a lucrative movie career, everyone and his brother wanted to be the next Arnold. Working out and bodybuilding in general hit it's peak as far as mainstream popularity around Haney's era of dominance.
So if there are a lot of people trying to be the best, and you are the best for a long time, you're damn good. And that same person would be good at any time period given a level playing field. Maybe that same person wouldn't be the best, or as dominant as he was, but he would still be great.