Higher property taxes for persons not subject to tax in Canada on their worldwide income just like in Florida where the assessed value is based on FMV.  This will capture significant local tax in areas of escalating property values. 
Tax the gains fully as income and tax the sale of purchase and sale agreements to prevent flipping. For Canadian taxpayers, capital gains treatment should be available only after holding the property for 5 years unless the conditions met to claim moving expenses are met. This stops domestic flips.
Mandate the purchase and sales agreements must include a clause allowing the subsequent sale of the contract only with the consent of the original vendor. That will instantly stop flipping and instill a moral fiduciary element to the real estate agent industry.
Insist banks retain loans made to non-residents to purchase Canadian real estate. This will ensure risk taking is properly assessed by the originators of the loans. No more CMHC backstop on such loans.