I've never heard that, and the Granite Gear and Osprey packs I use do not make me lean forward. However, I do perhaps lean forward going up steep hills and when occasionally having to use your hands to climb. I could see having to lean forward if the hip belt is not riding in the right place and the pack doesn't fit well- you lean forward to take more weight on to your shoulders and upper back and give relief to the hips. I haul my heavy float tube in to some ADK brook trout ponds, and I do find myself leaning with the heavy load- but it's with a frame pack. I would see if you could find a place where you could get fit for a pack and try one out in a store. You certainly don't have to worry about rocks and hills on the Batona. (Did it about 35 years ago). At that time I was using a Jansport D-2 external frame and carrying 35-40 lbs. Might do it again sometime in winter. Pack fit is far more important than the type of pack, up to about 30 lbs. Keeping your pack weight as low as possible helps a lot.