Amusingly, I took a look at Mississauga MTSA assessment from a couple years ago, and the only MTSA where they decided it just was not possible to achieve the density targets and nothing should change is Mineola, just north of Port Credit GO, which is the confluence of the soon to be completed HuLRT, soon to be electrified frequent Lakeshore W GO and easy access to QEW. That is a much more logical place to try to jam a dense office node. Ask the City of Mississauga? Not a single low rise SFH to be touched. Impossible! Of course, this has nothing to do with the wealth and influence of the residents in the area.
I don't think that cuts it as strong transit connectivity. North York Centre is on Line 1 and Line 4 near the 401 and not very popular as an office node.