Thanks jks.
What is really needed here is some forward thinking. In another 10 years, they're going to need yet another platform if the Yonge line is extended.
They should carve into the walls on each side, resulting on one loading platform for each way and one shared central platform to unload passengers. When a train arrives, doors open to the unloading platform first, then open on the other side to let new passengers in.
I guess you can say by building this wall in glass, it'll be easier to do this than if they bricked it up, but I sure hope they're taking other measures necessary to begin building a third platform soon after they're done with this new second one.