I respectfully disagree with your statement.
People go to Yonge and Sheppard to live. Using your example of the subway, look at the flow of people in the morning and evening. A huge amount of people get on at Sheppard in the morning to head downtown. Much less get on at Eglinton, and the subway empties dramatically at Dundas. In the afternoon, the opposite happens, with a large number getting on at Dundas, a considerable amount getting off at Eglinton, and the train basically empties at Sheppard.
Yonge/Sheppard is a prime example of a urban/suburban node, IMO. Yes, it can't compare to Yonge/Dundas, but that's because it's much older and obviously more developed. Yonge/Eglinton is heading the way of Dundas with its mixture of shops and living, but Yonge/Sheppard is still primarily a urban/suburban neighborhood. It's the place where young families can put down roots while still enjoying downtown life with only a 20-30 minute subway ride.
Decades from now, yes, Yonge/Sheppard will need (and will definitely have) alot more reasons to visit the area (other than those who live here) but for now, it fits. NYCC is developing quite well, and I believe that there's little need to artificially create destinations (shopping, entertainment etc) when those will naturally come in time as the area develops.
Already, Hullmark and Emerald are creating a much more impressive intersection that will definitely attract other great attractions. In terms of the future of NYCC, Hullmark and Emerald are definitely driving it forward.
It is disappointing that T&T is no longer the anchor tenant and is being replaced with Metro. The Whole Foods at Hullmark Center across the street already caters to the upscale market... a Metro is redundant.
Without T&T, I can see this causing a huge ripple effect with the other tenants. What this could have been is a mini pacific mall that revitalizes the entire area. A unique shopping hub that would have given people reason to actually get off the Yonge/Sheppard subway to shop. You go to Yonge/Dundas for the Eaton Center... you go to Yonge/Eglinton for the theaters and restaurants... you go to Yonge/Sheppard for... what?
Metro, Starbucks, and a Bank? Yawn.
If this were a sci-fi movie and someone wanted to go back in time to dramatically change the future of NYCC, this is the key moment.