So once people are in, ANY change is problematic. Increased density and construction is the common case these days because that's what we need, but the same would happen in reverse. If NYC's mayor said they were going to eminent domain the whole place to make it a low density suburb, even the people who get to keep their homes would lose their shit. You don't live in Manhattan because you want a big yard for your 6 dogs and 3 chickens.
When it comes to housing, any kind of change is hard. So if you start from scratch, there's not much problems.