NIMBYism is such a discourse terminating word. Every opposition to a project needs to be taken on its own merits.
Personally, as someone who is unlikely to ever be of the socioeconomic class that can justify living downtown, or, in fact, anywhere within the city limits of Toronto, I'd be happy to see the whole thing abandoned and Pearson expanded in its stead. Having a fantastic, beautiful waterfront without an airport spreading its tentacles all over the place would be a lot better to the long term health of the city than expanding BB. Those who want to travel can do what the rest of us plebs have to do, and go to Pearson. Life is so sad when it's viewed only in the context of the financial value of a given decision.