Did you even read the article?  
The current model is no rent controls for new builds and no rent controls for vacancies for pre-1991 buildings.
Imposing rent controls on post 1991 buildings means no developer in his/her right mind would build new.  Given that Toronto has grown by about 23,000 people a year the city needs about 10,000 new housing  units.
So without new rental units the rental market will get tighter and it will be harder to find housing.  Ethical landlords will abandon the rental market.  Unethical landlords with reduce maintenance to a minimum, if at all, ask for under the counter payments for new tenants and actively work to have old building declared uninhabitable so that the can be torn down.  Landlords will now have their pick of tenants and it will be the poor and marginalized that lose.
Some tenants will also ask for money under the table for subleases.
Rent controls are a disaster that hurts the poor most.