I think if there is enough space to provide first class, which there clearly will be between Swansea-Manchester with 5 carriages, then it should be provided. The Swansea-Manchester should be intercity IMO as its covering 2 major cities Cardiff and Manchester one of which is a capital city, another is seen as the capital of North England. Also there is Hereford and big towns such as Shrewsbury. It should be limited stop only calling at Neath, Port Talbot, Bridgend, Cardiff, Newport, Hereford, Shrewsbury, Crewe, Wilmslow and Stockport. All smaller stops should be picked up by a stopping service that runs hourly between Cardiff-Shrewsbury/Crewe in between the Manchester services.
I understand the plan is to run a Cardiff-Shrewsbury stopper with an extension to Liverpool every 2 hours.