Yes, if such a redesign is to be done, ARP will not be needed. MAC address is physical address of any interface and it is static. MAC addresses are unique around the globe so two devices will never have the same MAC and hence a device will eventually be found using its MAC address only. So when there is no IP each device will have this static address on each of its interfaces but it will be a nightmare to update and perform lookups on the basis of MAC because they are not hierarchical.