Right now the problem with the piazza is... drum roll please... money. Or more like not knowing where it'll come from. Estimated price is somewhere around a half million, which doesn't sound like that much but is if you don't have any of it. Also, the city will lose several parking spots if the piazza is created and no parking spots means less money for the city. And needless to say, one closed street could cause a lot of traffic hassles, especially in a neighborhood well known for being a traffic clusterf----.
The positives in the piazza are mainly in that it's a pretty frickin' cool idea if you ask us.