Something else to add, once a container is flagged, that flag could be accessible in some way from the autopickup manager.
You could, for example, make all your brass casings go to the same container when picked, or your arrows to go straight to the quiver. You could make, for example, that when you pick up a specific magazine or gun, because you dropped it just to shave a little more time while being attacked, it goes straight to the vest pocket or holster.
It might be possible to be even fancier: if you can flag containers in inventory, not just worn, you could, for example, flag plastic bags, and then use the autopickup manager to make certain things, like, say, food, go into the bags rather than loose in the inventory.
@TheZoneWizard: I’m seriously not worried about ‘assorted items on pocket’ being hard to find. Chances are, either the character was smart and placed them on that backpack in an organized way for ease of access, or the objects are varied enough in size that you should instantly be able to pick the right one.
Ammo in the pocket? A shotgun shell, a rifle bullet, and a pistol round are all of considerably different size, you should be able to just grab the correct bullet on touch. Oh, sure, if you got slugs and buckshots in that pocket you’re shit out of luck, but it doesn’t take a genius to solve that issue. A rubber band, some plastic or paper, or even just marking them with a knife would let you separate them on the pocket or tell the difference. I do not believe we need to model that, particularly because it’d just be added tedium you’d need to do before doing anything remotely interesting, so it’s better to just assume the character has a brain than force the player to waste half an hour of every game session on brainless inventory sorting.