It doesn't surprise me. Thanks for letting me know the details of what was going on BTW
Castlefield isn't the only bottleneck on the network, it's a big one, but not the only one. There is rolling stock, staffing and a lot of other congested infrastructure.
A lot of people look at re-organising services around the needs of Castlefield, forgetting there is an entire network of routes each with their own specific requirements.
The only way to address the issue is to invest in renewals and upgrades for the whole region (including Castlefield) to bring the infrastructure up to scratch.
Salford Crescent could possibly handle another platform, reduce bottlenecks there. Victoria could possibly add some more terminating platforms at the west side.
I'm sure there are other grade seperations, junction remodelling, etc that could be made to optimise movements.
Long term plans also need to be drawn up to decide on city and regional transport networks and the projected demand for journeys along the corridor, especially when HS2 arrives at Piccadilly. (May encourage significantly more people to use rail to reach Birmingham/South West especially). My thoughts are a tunnel, but it would be good for some studies and planning for that to be done, in preperation for breaking ground hopefully by the end of the decade.