I don't think anyone is arguing in favour of the creation of "projects", tenements or slums.
The solution (as usual) is multifactorial.
The "double taxation" assessment rates have to go. With the appreciation in real estate valuation in the last couple of years, the tax burden on landlords is becoming untenable. They have no choice but to pass the cost of property taxes to their residents, significantly increasing rents, and forcing low income residents out onto the streets. Higgs should address this situation immediately.
At the same time, ways should be found to prevent (or reduce) the sale of rental properties to out of province entrepreneurs from Upper Canada who then "renovict" residents so that they can increase rental prices by 70,80 or 100%. This could be managed by putting on "reasonable" rental controls. Of course, one cannot do this without also tackling the "double taxation" problem. The issues go hand in hand.
I am not against the idea of legislating a certain percentage of affordable housing units in new residential buildings above a certain size. Some developers of course might object to this for a variety of generally legitimate reasons, and I would allow them to get out of this requirement by having them instead construct affordable housing elsewhere in the neighbourhood (not on the fringes of town). Affordable housing should be available downtown.
For the truly indigent and the homeless, I like the new tiny home initiative that they have started in Fredericton. This gets people off the street, and gives them some personal dignity and a secure place to stay.
So, in essence, my solution would be:
1) - eliminate the double tax on non owner occupied residential units.
2) - have the province and municipalities tightly control the residential tax rate in order to prevent tax windfalls due to rapidly increasing assessments.
In return for this tax relief:
3) - institute reasonable rent controls on the rental properties (no more than several percentage points above the cost of living, with the right of appeal for extraordinary circumstances, such as unanticipated major property repairs)
4) - mandate the inclusion of a certain percentage of affordable housing units in any new multi residential project above a certain size
or
5) - in lieu of this, allow property developers to pay a fee towards the creation of government provided social housing units in the neighbourhood.