I personally hope that the WMT application gets selected over any of the open access ones if it's a choice between one or another as it will allow for a much easier and hopefully cheaper Manchester to London service as an alternative to the Avanti service from Piccadilly. It's also logistically easier capacity-wise given that it doesn't add any additional trains running south of Crewe.
It'll especially be welcomed by the those who live in North Manchester and currently have to trudge along the city centre from Victoria to Piccadilly.
One more-feasible opportunity I think OA is really missing is to run Manchester Airport-Euston semi-fast services.
The platforms there are due to be lengthened soon, and the station has a large catchment of residential South Manchester & North Cheshire, which has a substantial London market which the HS2 airport station was designed to serve. Whilst this is no replacement it would improve capacity, and (in theory) result in less congestion between Wilmslow through Stockport to Piccadilly which is a real bottleneck.
You could potentially have the existing Avanti service run fast from Stockport to Crewe flighted in front of the TfW service, thereby (again in theory) allowing another fast service between Wilmslow & Crewe (Originating at the airport) to be flighted behind it whilst not losing the line's stopper.
Having lived in South Manchester and North Cheshire, 8x out of 10 it's more convenient and faster to access the airport station than Piccadilly anyway, so it'd also be operationally beneficial in reducing pressure on the city centre termini a bit too. Adding extra London services using any of the existing central termini seems impossible to timetable without importing risk of delays.
Not to mention an airport service would be beneficial for passengers from the West Midlands who might prefer/need to access Manchester over Birmingham International or London airports.
Whilst a service via Victoria might be of more utility for people in North Manchester, the delays it risks importing onto an already highly congested city centre network are serious. You can bet if something goes delayed the OA operator will get priority over the (arguably more social-mobility important) local services. Instead the focus should be on re-timetabling the city centre through-running services to have an additional services over the Chord. That means a Castlefield service would need to be moved to Victoria yes, but from an operational and utility standpoint it would me a much better compromise imo.
Ultimately everything is a sticking plaster until central Manchester sees the east-west relief tunnel it so desperately needs, but that's another topic!
