I don't think we can avoid building new. Our population keeps growing and we need a place to put them.

What I would like to see is planned building. Designate an area that could use increased density (like say, along the Sheppard or Downsview Park subway lines) and plan a mixture of building types, green spaces, additional transit options, etc. Developers always want to build in close to the core where there is already high population density because they can charge more for the finished units. Instead the city should be telling them where they can build and how much.

I also think we should get rid of forced "back to the office" and re-purpose the empty office buildings. Offices do make sense for people who can't work from home, but it makes no sense to force people to move back into the city just so they can get into an office they don't need in order to do their job.