Mississauga grew after or at same time as Scarborough, Etobicoke, North York. Mississauga is neither unique nor was it the first. If Mississauga's growth was truly uncontrolled, this thread wouldn't exist. Erin Mills Town Centre wouldn't be surrounded by undeveloped land for future high-rise development (the Central Erin Mills node). For uncontrolled growth see Brampton. Just pure houses, no high density there.
I live in exempt part of airport operating area beside Heartland. Noise is already bad enough, imagine people living even closer to the airport.
Heartland is no better than the power centre at Winston Churchill and Argentia. Isolated, beside highway, in a cheap industrial area, designed for people to drive to and from store to store. In other words, just another power centre.
If Heartland was designated as a node, it would be the only one not located beside a transit station or a priority transit corridor. And even Square One doesn't have enough transit for the parking lots to be redeveloped.
If the city wants more residential in the airport operating area, then building around the LRT station and office buildings at Hurontario/Britannia would probably make more sense. Lots of undeveloped land there too. Much easier and higher potential.