One of the great frustrations for me right now, is the Scarborough subway debate. The Scarborough Town Centre (STC) was built to be away from subway and on the highway network, as a decision when it was first built. It was also built in order to make the car the primary means of access (hence the massive parking lots). The then city of Scarborough reduced the zoning density around Kennedy as a matter of policy, and now we are going to build subway to the STC.
I mention this, not because I believe that the Scarborough debate is a particularly bad situation, but because it is far too typical of the debate surrounding transit in Toronto. Subway as the go to solution, where there is a clear need to get many more riders onto transit, and that means better rides, and more access across an area that we simply cannot afford to build subway. Advocating for subway as a wider solution is essentially saying that we can afford to build it and operate a massive amount of it. Toronto, was simply not built that way, and we need to start to deal with the needs in a context of what has already been done. If people are going to be attracted to transit, it needs to be faster than a bus stuck in traffic, but that does not mean subway everywhere.
The vast majority of access will need to remain basic bus, with a large amount of BRT and LRT added in areas where they can in fact be built. Where there is a corridor that can act as a closed express corridor, there is the option for higher speed more direct transit. These need to be part of a set of building blocks that reach across the region.
Toronto, needs to start supporting a serious increase in density, and much better access to transit, but subway should only be added at the point where there is a very real capacity requirement (ie something to relieve Yonge). Otherwise, Toronto, needs to build a transit network that matches the density that it has, and is likely to have in the next couple of decades.