Toronto does not have enough parkland Downtown for a city of its size - unlike New York with Central Park, Vancouver with Stanley Park, Brooklyn with Prospect Park, San Francisco with Golden Gate Park, Montreal with Mount Royal, London with the royal parks or particularly Chicago with its incredible waterfront parks.
Toronto is talking about a 1.66 billion park over the railways - about $80 million per acre, and while some small parts of this make sense, this is not affordable and there is no money for it.
Meanwhile, the 3 levels of government also are spending billions on the Portlands. Will this turn a profit? No, in the end the land will be some parks but most of it will be sold off for condos.
If Toronto ever wants a World's Fair, or an Expo, there is no place for it to go - in 100 years, Toronto will be even denser and the people in Toronto will ask why nobody ever created a large park - Toronto Island is hard to get to and the ferry is not free.
Rather than spending billions to remediate the Portlands, stop the current plans and instead reserve it all for public uses and parks - no condos, and gradually eliminate the old industrial uses and replace it with sporting facilities, art galleries and make it like the waterfront in Chicago.