Well they could be potential markets. I personally think that Lumo would make the most sense to stop at Newark, then GC, then Hull Trains.
Why Lumo? Newark already has a perfectly satisfactory service to Edinburgh and Newcastle, and I highly doubt that there is great demand between Newark and Morpeth, or indeed Lincoln and Morpeth.
They said they wanted an OAO as they think that it can provide needed competition to LNER. I was suggesting Bradford and Sunderland as starting points for said service. If you want LNER to operate an additional service, it would make much more sense to start it from Doncaster, York or Leeds than Newark due to passenger demand, staffing and turning around trains.
Before the bi-modes came in, what I believe are now the Lincoln Central services terminated in Platform 3 at North Gate.
From my experience of people in Lincoln/passenger flows in Lincoln, the main demand that remained untapped when I lived nearby was to Kings Cross and back. Now that's there, I don't see what else could be improved except possibly a better service to Doncaster for connections there, or even just retiming of the Doncaster services so they alternate with the North Gate services (as opposed to two broadly two-hourly services leaving fairly close together) for ECML connections. In short, Lincoln is basically sorted, short of building a new railway. Newark is very well-equipped for intercity services, and Lincoln is very well-equipped for local services, so they complement each other. Again, I can't see any real benefit to making anything else stop at Newark - everything vaguely realistic is already dealt with, especially if you're coming from Lincoln (which certainly used to be a large part of the catchment area for intercities, no idea if that's changed).
Bradford could be a potential market from Newark, so could Sunderland.
So people from Newark
might want to go there after all?
Are you using some kind of reverse of what I call the Heritage Act logic, the Act in question meaning that no museum object can be restituted unless they are 100% confident that nobody, ever, present or future, teacher or student, will have any interest in said object? I.e., that a service should exist as you are not 100% confident that nobody, ever, present or future, will use the service?
If anyone from Newark wants to go to Sunderland, they can change easily at York. For Bradford, change at Doncaster and Leeds. While it is a pain not having regular weekday LNER services from Newark North Gate to Leeds, an OAO proposing to run Leeds-Kings Cross stopping at Newark would a) have a job filling up seats considering they presumably wouldn't be allowed to call anywhere else (except somewhere like Huntingdon) and b) not get off the ground anyway.
Newark and Lincoln are perfectly adequately served by LNER and the regional stopping services. OAOs aren't sweeties, the good people of Newark won't get annoyed at not having an equal share.