Jackson Sq only takes up a lot of the "used downtown". I would argue its the only thing left anchoring any major activity downtown. Without JS right now there wouldn't be much else. It would seem less overwhelming if our downtown lively/commercial areas extended (like it should) along York, King William/Wilson to John.
Depends on what you mean by downtown as well.
If the light pink is downtown its a small fraction. If you mean the CBD (red) it is a large area yes indeed. But it's more then a mall. that footprint is also four office towers, a library, a market, a hotel and you could include Copps too.