If an item stacks to 5, that means wicker picker is essentially 4 inventory slots which you are trading for a valuable hand slot, and you wouldn't even equip it merely for the 4 slots.
This is because of the fact that all the unstacked items will need to be manually restacked when you store it, which takes more time than just doing another foraging trip. This makes it by far the worst item in the game, because it is the worst kind of useless, an item that actively hurts you.
Compare it with the wanderers bindle, another early game item. You get more than 4 inventory, but with none of the wicker pickers horrific drawbacks.
It would be nice if this fun early game item received some of that lobtar love.