There is not, and never will be world peace. So the idea of creating an organization to accomplish this, is a waste of time, energy, and resources. And for the time it has been around, no, most of the problematic countries won't even attend meetings, so what's the point of having this organization.
UN has served it's primary function of avoiding war. It has helped in the stabilization of world economy. It has served other works like helping the needy and making the socio-economically weak masses the safer ground to live in. But the stronger hand of the developed nations in the UN is definitely needed to be avoided for the betterment of the world peace.