I think it might be worthwhile for some to have a better understanding of how that space is laid out:
I have used the area function of TO Maps to illustrate the rough footprint of the mall atrium if pushed through on a straight angle to the Dundas arcade . (it would actually have to angle to the right w/the glass to the right of the office tower).
But the key here is understanding that there is no functional room for retail on the west side of the main corridor if you choose to keep it roughly straight, the retail would be entirely between Yonge and the main mall corridor.
There is some space available to the west as you move further north; but it does make for challenging design choices.
Steering the corridor to the east/right does allow for equally demisable space on both sides, but throw off what I would think of as the ideal mall corridor visual.
Either way, you have to choose whether you want any retail to animate the Yonge frontage; and if you do, providing it connections to both the street and the mall is a bit of a hassle for store security, with conventional retail tenants.
It can all be worked out. Just have to see what CF wants, and whose in the market to deal.