The way I see it, the % doesn't matter. Our carrying capacity for the change is what matters. Maybe our infrastructure could handle 5%.
Our levels of immigration over the past decade+ do not serve the existing or new Canadians in the GTA well as the housing expense has become too high. Transit like the Finch LRT could have been put in 20 years ago as we've always had strong bus ridership (assumption) without the gentrification pressure (see the lack of investment on the Danforth line). Now, any area that has the slightest public investment will be poised for gentrification due to housing pressure.
So, what you're saying is... let's make sure we are always building transit in the city, so that we don't lose all of our local skill base, the skill base we now actually have again.