Put that way it doesn't seem like it would've worked well, if the line speed had remained low. What was the top speed on the Market Drayton line before it closed?
I know parts of the North Staffs are fast, but it's not just Stone that has a slow section - the train always crawls through Macclesfield and the new line around Harecastle hill isn't very fast. A little off topic but it seems a bit odd to have all services through Stoke station stopping there, perhaps things could be sped up a bit here.
Have you looked at the population of Stoke? Bigger than Wolverhampton, for instance, where everything also stops.
If the NS line is "slow", why is it the prime route from Manchester to London?
The biggest bottleneck on the Birmingham route has been completely eliminated by the Norton Bridge flyover.
The future fast route from Manchester to Birmingham will be HS2 (missing all the stations mentioned!).
I don't know about the Market Drayton line speed, but my guess would be around 60mph.
It's traffic was local stoppers, GW freight and the odd mail/parcels service, I think.
The Stoke-Market Drayton branch just added locals and freight to the southern section.
There was milk traffic to a creamery en route.
The Bushbury connection between WR and LMR was also in use at the time, I remember a Snow Hill-Stoke-Manchester service routed that way while the Stour Valley line was being electrified.