Northern Light
Superstar
just kill VIA service entirely on the north line and run all VIA trains through Brantford. Run semi-frequent GO service on the north line with upgraded infrastructure.
That would make a Windsor-Kitchener trip impossible without a transfer at London.
I don't think it make sense to eliminate that possibility.
I want there to be connections from as many places as practical, to as many others as practical, and certainly between larger urban centres in SW Ontario in this case.