I don't think skip stopping the likes of Aughton Park and Town Green, or some of the very quiet Southport local stations, giving a half hourly service, would be entirely unreasonable. But we don't want to slow things down *too* much. Ten minutes on the Ormskirk since the system opened is quite remarkable. Though the 777s may be able to claw a bit back.
It would complicate the system but if it was numbered German style it could be quite clear that you want the N1 rather than the N2, or the W1 instead of the W2.
The trouble with skip stopping is that it would ruin local journeys, and Merseyrail is quite well used in that respect, which is to be encouraged not discouraged.
Were it possible to be pathed, and could be made commercially viable, something like a half-hourly express service to both Southport and Ormskirk would be rather good, on top of the existing service. In the case of Ormskirk I’d be looking to call at something like Kirkdale, Aintree, Maghull and Ormskirk only. Less sure about the Southport line but there I’d be more looking to include the stations at the Southport end and run fast nearer to Liverpool.
But it’s all pretty academic as there’s a number of reasons why this just isn’t going to happen. The best enhancement Merseyrail is going to get is from the enhanced performance of the 777s. And, really, a more useful improvement would be increased train lengths.