Recently read all the comments and find it interesting that the most challenging thing facing this site has yet to be mentioned. This property is sitting directly on top of a buried river. This most likely prohibits significant below grade construction and makes the foundation construction possibly very expensive not to mention the Toronto and region conservation authority jurisdiction that this falls under. This also likely won't be dealt with until site plan approval is submitted for and won't be addressed during the rezoning process. It is likely that this will be major factor developing the site.
It sits atop Burke Brook, which is in a pipe here.
The pipe is actually City (Toronto Water) jurisdiction.
Here's an overlay map from Lost Rivers showing Burke Brook's route through the area.
The long red line is Burke.
The TRCA floodplain map for the area shows no regulatory floodplain at Yonge:
I could stand to be corrected, but I believe the pipe actually passes south of this site, either beside or under Muir Park residences.
I'd have to look up the sewershed drawings. Suffice to say, I don't think that's a material obstacle.
There are buried streams built over, all over the City.
Don't get me wrong, I'd love to see the creek daylit here (it's above ground partially in Chatsworth ravine, and then surfaces in a concrete ditch in Alexander Muir.); but I don't see that happening.
