The actual live letter slide (http://forum.square-enix.com/ffxiv/a...3&d=1455093098) says:
"The ability to meld materia will be expanded to various types of equipment." instead of being applied to all equipment.

It's unlikely that the i180 will become meldable, as that would go against the entire point of having i170 meldable/i180 unmeldable gear.