That's the plan but I believe we've yet to see anything materialize in terms of developments, or even proposed developments.I thought the plan for the Downsview Park lands was to like 10,000 new housing units to the area.
This UT article mentions no development in the vicinity of Downsview Park, other than Centennials aerospace school: http://urbantoronto.ca/news/2017/02/growth-watch-2017-downsview-york-university
Same thing for UT's development map: http://urbantoronto.ca/map/
And obviously, driving through the Downsview Park area, you see no redevelopment going on, other than the subway station itself. The plan is for 10,000 housing units, but it's looking like nobody is interested in building in the area.