The belt line isn't plowed and at this time of year when it's thawing is nearly impassable. That hill is very large, about 75 feet vertical straight up then down again, and crests one of the highest points in the City of Toronto. There is much local demand at that point, and the buses on Spadina and Chaplin were targets for the Ford Service Cuts.
It is an urban subway and should be operated with urban subway stop spacing. 3 stops per concession is perfectly reasonable. This is not an instance where we should be building suburban-like stop spacings as the majority of the demand is indeed relatively local in nature.
The net inconvenience to crosstown riders (who probably number a few hundred a day) pales in comparison to even the number of high school students that wll use that one station in the 45 minutes after school lets out. Chaplin needs to be there.
Oakwood, too. Being skipped by transit would be a nail in the coffin for an already struggling area. Why spend 6 billion dollars if you're just going to bypass your users?
If we want fast crosstown service there should be express GO service, possibly on the North Toronto rail line. Crosstown rides should not be brought about at the cost of local users. Subway is not regional rail even if it's used as such in Toronto.
This is one reason why Transit Planning in Toronto is so flawed. We keep hijacking what should be local services into regional services. This hijacking is exactly why the LRTs were doomed; instead of providing moderately improved local service or midrange commutes, we instead decide to build lines for the 10% of ridership that is going more than 8km on that line usually to the detriment of those that are travelling locally. This is exactly what happened to the Sheppard LRT. The subway plan provides a rapid connection between STC and Downsview but makes travel on Sheppard itself much less convenient unless you live right beside a station. It's the 500 passengers a day that ride Downsview to STC that the line is built for, not the 60,000 a day that are travelling shorter distances on the line itself or to change to another line elsewhere.