Just to clarify, the A in MRA 4 is to emphasise the attack capability of the ac using Harpoon AGM 84 in a maritime role. It was, and is, designed as a maritime platform. That the present MR2 platform undertakes other duties at present will have to will need to be addressed after the ac enters service. To add capability during development is called requirements creep and cannot be undertaken without incurring cost and time delays.
I was once told by a crew chief that ASW stood for Any Sort of Warfare, I guess he was right.