DENTROBATE54
Banned
Seriously? Okay, downtown Toronto would be 200% easier to commute around. The 503/504/505 would be converted to regular service buses hance 10 min headways awaiting slug-speed streetcars would be a thing of the past. Everywhere from Mimico, Swansea, Parkdale, Queen West, Chinatown, Moss Park, Riverdale, Leslieville and the Beaches would have seemless transit options and likely wouldn't be overrun with condos as BD is still largely unaffected by condo and skycrapers.
In the long term the line could've extended at both ends, in the west to Sherway Gdns and Mississauga and in the east up Kingston Rd perhaps to the Stoufville GO line and veer up it, such that it'd supplant the need for a SRT in the first place.
For suburbanites perhaps the crowding of the Bloor-Danforth streetcar would've been appeased by the presence of a subway directly in the downtown core. As such the then Toronto's suburban periphery (Eglinton) would've received the secondary east-west subway line and extend across the length and breath of Eglinton from Pearson Airport in the west to West Hill/UTSC in the east.
So as it turns out placing subways where people actually live and work (not in hydro/rail corridors) could've spared millions of people over the years arduous commutes, trying to make sense of the several transfers required just to make a single trek across the 416.