Rail House in Crewe is a 1960s eyesore, and would need some serious investment to bring it (back) up to a usable state. Demolition would be my preferred option. The Annexe building (2-storey building facing onto Nantwich Road, linked to the main building by a footbridge) has already been converted into residential accommodation.
Assuming Phase 2B of HS2 goes ahead, there's a case for expanding Crewe station to have platforms on the Independent Lines, so a new station entrance where Rail House currently stands would be ideal, with a new office building above. Maybe cover over the Independent Lines with a ramp, to create better access / egress, and car parking too.
I've no idea what the current plans are for Crewe station in the long term, merely speculating as to what is possible ...