Currently, the backpack is a little counter-intuitive for your hearthlings. Hearthlings can carry a maximum of 4 items, but it usually looks like their backpack can only hold 3. When they pick up the last thing, they hold it in their hands while they carry it to the stockpile. So the last item never actually appears in their backpack pane.
Now it’s great that you can actually see the hearthling carrying a thing, so that should definitely stay. It keeps them from looking like they are just wandering around doing nothing. But I do think the backpack pane should include what the hearthling is holding.
I would also add Backpacks to become a craftable upgradable item.
Upgradable Backpacks
This way we could have a sense of growth in our equipment by allowing certain classes to have bigger or not backpacks than others, also would develop throughout the game.
Right now we begin the game with our Hearthlings equiped with a default backpack, I would have the game begin with no backpack at all in order for us to be able to get that sense of growth and improvement in our settlement as we advance in the game.