"UN is a village council for the world"
In the long period since 1945, the world has dramatically changed. Though the General Assembly of the UN is not an operative body, it has done a lot to the world. Every little state can come and speak here.
They started a lot of movements (including the human rights movement), started the discussions on the environment and global warming, changing the law of the sea, changing the maps of continental shelves.
At the same time, the Security Council of the UN has become significantly more operative, but it depends on the agreements of the permanent members.