Micro segmentation is based on filtering endpoint traffic directly on the access port. This allows SGT-based filtering even for clients within the same L3 network.
Based on that, MX (from my point of view) is not the place where „micro“ segmentation would take place. It‘d rather fulfill firewalling based on SGTs instead of IP addresses with inter-VLAN traffic just as ASA and Firepower devices already do. It‘d be a great choice if MX could handle that too tho 😉