My Step Son is a budding (well on his way) professional photographer and has been going through "back packing packs" like crazy to find one he really likes and has a couple real nice ones now that work great for when he packs into high mountain lakes and such. I have really looked them over and couldn't imagine using one for the kind of "off trail" hunting I and I am sure most of us on here do. For reasons others on here have already stated.
Another HUGE reason I stay with "hunting" packs is that I KNOW these company's support my (Our) way of life!
Who knows what kind of anti hunting groups some of these "granola companies" support.
You will get my EXO pack off of my back about the same time you pry my gun or bow from my cold dead hands!