I've just moved back to TO after 3.5 years in NYC, and the express trains there are actually now beloved by many—folks walk long distances above-ground past local stops to get on an express. For one thing, it allows some people who live in less expensive neighbourhoods reasonable-length commutes to their places of business in central Manhattan.
I'm not sure the RL would afford the same benefits for a few reasons, but I support it because the Yonge line is already so massively over capacity (and will only worsen as the population continues to grow).
I also live in the neighbourhood and welcome the added density, though the design definitely leaves much to be desired (as does so much new and recent build in the city). I'd love to see developers choose to be more ambitious in the designs they propose, both in built form and in public realm considerations.