I believe if there is any location to speak about socio-economic impacts, this is it. On first examination I see two main difficulties: the loss of heritage and the out of context height of the proposal as well as the absence of social housing in the discussion.
Regarding the latter, social housing (or affordable housing) should be a priority throughout the city, not only in one area. The concentration of poverty here is palpable yet serves the interests of none. I too believe Regent Park should have added some more units, but the creation of mixed income zones benefits everyone in my opinion (social procurement in building, jobs at the local businesses like banks and supermarkets that didn't exist previously, new, excellent quality facilities that almost nobody in the city has in their 'hood). At some point fairly soon we should expect Moss Park to get redeveloped, with the large number of parking lots fronting Queen and running up to Shuter being part of the development. That might be a great place to add more affordable housing right here.
As to the development itself, there have already been new builds around this area, so this one won't be ex nihilo (the Sherbourne and Richmond building in particular but also the development along Adelaide, George and Shuter, 88 Queen East, etc.). The area has been gentrifying for the last number of years. But the scale is jarring. It will significantly alter the area and likely set a huge height precedent. However, if a subway is to come through Queen St., I don't know how those of us concerned with heritage retention can reasonably argue to keep all the three storey buildings intact - which is but one of my reasons for preferring a King St. alignment. We need to seriously get our act together as a city to decide the future of a Queen Street that has a subway. More density and height will be required all along Queen as far as I see it. However, I do not see why we shouldn't demand better integration of these heritage structures.