We need that Hauling rewrite desperately.
Ekhm. Why?
There are plenty of efficiency reasons for having stacking and hauling, so that dwarves can put a stack of 5 plump helmets together with another stack of 5 plump helmets in order to conserve space in the stockpiles, or having to go back and forth from the fields carrying each seed to and from the fields individually, or making looting the goblin corpses a matter of the
entire fortress population each running out into the battlefield to pick up
one sock each while the iron breastplates lie unclaimed until the next siege.
Aside from the obvious immediate uses of having dwarves capable of carrying and storing multiple items together, it is necessary in the long term to allow DF to break away from its materials rut of everything costing 1 wood, 1 stone, or 1 plant, or 1 metal. Make a barrel out of wood? That costs 1 wood. Want to make a ceramic pot, instead? The clay is free, but the fuel costs one wood. Material cost-wise, it's all just 1 wood.
Costs in stone are pointless, since they're so abundant as to be a benefit whenever you can get rid of the stuff. Farming is so easy that plants like food and booze and cloth are functionally free, as well.
That makes metal and sometimes wood the only resources of any scarcity or value.
The hauling rewrites are a prerequisite to almost any serious work on the industrial workings and economy of Dwarf Fortress, because it lets you finally start making one thing cost more materials than another thing without making that cost "3 metal for a table" when 1 free stone does just as well.