Perhaps a Manchester to Hartford service along the MCL would be useful? The trains going between Liverpool and Birmingham would be a useful thing to gain access to.
You wouldn't be able to access Hartford without a new chord being built, but you could go to Acton Bridge, and with some additional signals, reverse in platform 1. You would also need to fix the level crossing issues that are currently preventing any increase beyond 1tph on the Mid Cheshire Line.
It also wouldn't exactly be easy getting a good path all the way, but you could probably manage something reasonable - and the MRTF consultation did propose for TfW's Chester/N Wales service to be diverted via the MCL, so clearly it's within the realms of feasibility.
The biggest issue I see with the whole proposal is the question of what market you're trying to serve. A link from the MCL stations to Liverpool, Birmingham etc. would be
nice to have, but with the best will in the world, it's unlikely to fill trains. Certainly if the MCL and WCML were being built now, you'd likely build an interchange station where the two meet.
For example, Worcestershire Parkway has primarily been built to provide a quicker "railhead" option for from the Worcester area to Birmingham, and for shoppers and commuters to be able to avoid the traffic in Worcester. It wasn't really there to provide quicker links from the likes of Evesham to Cheltenham or Birmingham, as nice a side effect as that is.
The biggest market I could see would be for something like a Manchester to Crewe via Northwich and Middlewich service - which would provide the twin benefits of providing an (ideally) half-hourly frequency on the busier section of the MCL, and improving connectivity between the towns of that part of Cheshire, whilst also giving them a better link to London, Birmingham etc.
But even something like that seems unlikely, as there would have to be a lot of investment on the Middlewich line to build a new station and increase linespeeds. And it would effectively rule out any chance of the TfW service being diverted that way - which 'condemns' it to running to Manchester Victoria in the long term, and ultimately being split to become a second Chester-Leeds service in all likelihood.