YE station pedestrian dispersal network should be a legible gateway of distinction
I don't think any additional underground retail areas are needed, other than what's already there at YE centre & the subway tunnels. Also YE centre is expanding already, and there is already a lot of retail on Yonge north & south.
Glad you raised underground retail in conjunction with the YE subway tunnels.
I prefer to think of this space as the YE transit 'dispersal' area rather than subway tunnels. According to the projection I foresee, the Yonge Eglinton Urban Growth Centre will accommodate an additional population of 23,000 within fifteen years, equivalent to the existing population residing between Yonge-Mt.Pleasant and Keewatin-Merton in 2006 (figure from City of Toronto Neighbourhood Profiles).
Much of this population we want to see as being transit- rather than car-oriented, and frankly it will have to be. YE's arterial road network is tapped out at rush hour and this condition is unlikely the expand. So most people will be going down the 'hole', which should be recognised as YE's principal 'gateway' – the new, new thing giving YE its future recognition.
At present we endure a choice between either accessing transit through the crappy tunnel routes or crossing the rush hour congested YE intersection at grade. As we move forward into the future's population forecast, and recognising that the subway station is southwest of YE whilst the majority of the future population will reside east of Yonge and again north of Eglinton... it requires a principal pedestrian flow path to accommodate this movement.
There is a tremendous amount of space which will be open-cut to install the LRT station, a train-stable and switch, which it is then planned to simply backfill!. The overall length of open-cut will be in the neighbourhood (no pun intended) of Henning through to Dunfield.
Some challenge this gateway dispersal concept citing insufficient height traversing under the Yonge-Eglinton intersection, which I agree is a critical constraint. However, you if you use the stairway to grade within the southwest station entry, it involves 25-steps each rising 6", accumulating to an overall 12.5-foot difference between levels. Within this, a 9-foot high channel will be available, which can then then flare out to a greater height beyond the intersection.
There some who question the collision with underground services theat we presently dodge under. When the cut is opened up to its 21-meter depth, equivalent to condo excavations today, the services issue will be seen as a relatively minor part of the whole equation, worthy of relocation within the excavated void.
Besides practically accommodating the increased flow of population, and besides providing a gateway experience in this dispersal people... there is the further opportunity for local retail to treat the flow-through of transit commuters traversing through Yonge Eglinton as valued foot-traffic supporting additional retail enterprises. The broader the local retail offering, the less need for those living at Yonge Eglinton to seek destinations further afield. I consider this an astute win-win. On this basis, in this location, I do believe that another layer of retail below that at grade is a most appropriate, beneficial and desirable ambition to achieve.
Cheers
T