Yes 100% agree. The GEXR line is the only option for dedicated VIA rail in South-Western Ontario.
VIA needs to purchase GEXR from CN and upgrade to Class 6 177kmh from London until it meets the Metrolinx line in Kitchener.
Any other idea is pie in the sky, and missing Kitchener-Waterloo on the way to Toronto is idiotic.
There is potential in buying all the CN line from London to Windsor, its not CN's mainline, but I think its a little bit less necessary than the GEXR, as the sub to Windsor is in better shape and is pretty quiet for freight anyways.
The GEXR bottleneck isn't even freight, its that it has a top speed of 40mph.
Any idea to use CN or CP mainlines for improved VIA service should be squashed, its a non starter and a good way to waste money. Look at the 2000's corridor tripling fiasco that VIA went through as proof. Never again.