Locations along the Spadina line at and north of Lawrence are slated for massive redevelopment. Tens of thousands of residents and jobs. They can take the subway to Yorkdale. Yorkdale needs every single parking space it has even with a well-used subway connection. On a busy shopping day like Boxing Day, each space will be used something like 10 times over. They could add a condo with 200 units/300 people, but unless these people are shopping 10 times a day, the mall is much better off with an expansion of stores and/or parking. There's vast amounts of expendable land around Sherway, STC, Square One, Markville, etc., for the city to be better off by merging land uses and appeasing mixed use fans who think every last bit of the city, no matter what sized site you're looking at, needs to be mixed use. If new residences go in on the west side of Dufferin, that's still mixed use on the neighbourhood scale. They might drive across the street to the mall rather than walk, though...
An Arc-en-ciel renovation and a rebuild of the bridge to the subway would both be wonderful. If they're not planning to do them now, they might yield to pressure. Actually, a hotel would be a good fit. Yorkdale could become a stronger tourist attraction.