@HSTEd says upthread that a small station in Manc would be far too small - which I am pleased to read, so let's hope that others rrecognise it and we get some proper investment in our infrastructure to do it right. But why waste money on a terminating station, when you are already on the way to Yorkshire?
If it's worth running Eus Bhm trains through to Glasgow and Edinburgh now, why terminate future Euston trains at Manc when you could run on to Leeds and York?
which is very like my thoughts (a decade or 2 ago) on the original plan for HS2: I thought it should have run through a smaller station at OOC and on to Brighton. It would have relieved the current Brighton Main line, reduced land-take and cost in London, put (servicing) work into a coastal community - and would have dramatically improved connectivity between the South coast and the midlands and the N