The only involvement in gentrification by the city should be to ensure that any new residences be in conformity with the existing character and aesthetic of the neighborhood.  Single-family homes should only be replaced with single-family homes, and they should not be appreciably larger than the existing ones.  Mansions in a lower- or middle-class neighborhoods just don't look right.  There are plenty of places for mansions that don't detract from the existing neighborhood.  I would honestly prefer to see people buying homes, fixing them up, and living in them like the gay "homesteaders" do.  In this way, a neighborhood is improved, along with property values, without displacing anyone.  I'm just not in favor of all this tearing down and building bigger.