1. Art. Union Square is a full of artwork. Restrictions concerning street art.
2. Union Square park. Closes at night, sketchy in the daytime.
3. Rats and roaches in the restaurants.
4. Holiday market takes all the space. There is no place for skateboarders, chess-players, and all these weird people to hang out
I think the first idea would be the best because you can get a good depiction of two different sides. There are some people who may favor the restrictions, while artists and viewers alike will probably protest it. The story about rats and roaches in restaurants has potential if you interview restaurant owners and public, but it could be tricky to make it a two-dimensional piece.