The regular commuters from Warrington, Birchwood, Widnes and South Parkway want to retain the semi-fast services to Manchester and Liverpool, not have them replaced by an all shacks crawl.
I think the best near term solution would be to split the stoppers at Warrington Central, so that the eastern and western halves could each provide a 2tph clockface timetable at all stations without delaying the semi-fasts. It would require additional diagrams, but there would be a substantial uplift in patronage from the improved frequencies. Particularly at the Greater Manchester stations that currently only get 1tp2h.
I believe there are sidings east of Warrington Central that can be used for layovers.