There is absolutely nothing practical in any way, shape, or form about a 100m ROW at-grade quasi-highway boulevard with high density residential development flanking it on both sides. That would be comparable to living directly on a 400-series highway and such a thing would never get past an environmental assessment, let alone be allowed by the province as a replacement for that segment of the 413. At least with a highway corridor, you can sink the highway below grade, use earthen mound noise barriers, and surround it with green space or industrial/office parks, while densifying the rest of the area to make up for the lost residential space.
I also love how this plan is supposed to be a more "progressive" option than the previous iteration of the plan, despite the fact that most of the land remains dedicated to low density housing.