First off, I have never hauled out any game animals, whole or quartered on my back heavier than a ring-necked pheasant and that was in a shooting vest game bag.
Secondly, I have never had to haul radio equipment, crates of food, crates of ammo, or anything of that nature as a matter of necessity on my back.
Thirdly, I have never had to drag anything or anyone in a roughly made sled out in the back country as a matter of necessity.
With an external frame pack, all the above are possible. The frame could be a solid base for addition of native material to make a decent hauling sled.
I own a humongous Wegner (Total cubic inches unknown.) with 6 side pockets and an aluminum ladder style with turnbuckle cross tensioned external frame. I have a medium sized Hillary with 4 external pockets and an aluminum ladder style external frame. A boy scout small frame backpack (Which I will be selling soon or give to my nephews if any of them show a proclivity for the outdoors.) with ? external pockets and an aluminum external frame. An alice medium backpack with 3 external pockets, hydration bladder pocket, and an L1 steel external frame which I will be buying an equipment lip for.
I know from having been on this forum that most of you go on trips and do things that I would have been physically challanged to do even in my youth when both my knees worked well. I understand the preference for internally framed back-hugging packs that usually do better for balancing when you climb or hike meandering paths. I do not dispute those advantages and for the most part your selections make good sense.
What I like about external framed packs is the OPTION they offer for everything I mentioned at the beginnig of this post. Some have written in the past that your own legs will be your last available mode of transportation and wheels for lugging what you take along would make sense. With an external framed backpack, you can even jury rig an axle to the frame to support wheels.
One more thing, I like being able to hang the packs on a tree limb without having them sag, and to put the pack on wet ground where the frame keeps the pack from touching ground.
I do have a Jansport (Rucksack, Bookbag?) for in town use.
Bountyhunter