If you owe more than the house is worth, that is not a pleasant place to be, especially if you are required to move for any reason. or your house/ condo doesn't meet tomorrow's requirements.  

Any time gov't get's involved, they have precious little insight on unintended consequences that may result over a simplified solution.

Most Canadian's net worth is based upon their ownership of their principal residence, to remove five perhaps ten years of appreciation thru no fault of their own, is, in my opinion is somewhat short sighted.