Absolutely would help, best way to get people away from the stadium is to give them multiple options, so they can walk, train, tram, bus etc. People will find their own and quickest way home the more options you have, like when there is traffic from a crash or whatever so people start using the "back roads." When there is only one way home your screwed and have to sit in the traffic.
I know plenty of fans do go North or East from the ground, but vast majority go South or in to Mcr, tram isn't good enough and traffic backs up quick. Just not enough options.
Problem is I can't see MCC or City sorting out the goods line to accommodate fans. It would be just too expensive and not used enough to justify the cost. It would need to be part of a bigger plan or project. Can it link up to somewhere like Stockport who are desperate for Metro/light rail as if we chipped in for something like that MCC may get onboard?