Not sure I get the aversion of taking the pack off to get into it. I carry 30+ pounds most days in an Osprey Kestrel 48, camera, lenses, first aid, food, drink, fly boxes, jacket, mouche spry, etc, feels good to take hit off. Also gives me time to slow down, watch the water, take in my surroundings. But that's just me...
cheers
cheers