Which theory is criticized as being outdated for failing to explain why men should be assigned categorically to the instrumental role and women to the expressive role?

The theory that is criticized because it id deemed as outdated for failing to explain why men should be assigned categorically to the instrumental role and women to the expressive role would be the functionalist theory. It sees the society as a complex system where the parts work together promoting stability and solidarity. 

True. you know, tools like shovels.