I agree that this should be under the control of an international organization, but the UN is unlikely to be an impartial or intelligent arbiter.
Except 5, other countries don't have a permanent say in the system. The 5 can veto any resolution. The sad reality is that UN has been successful on various issues (while still failing on very many) despite being an utterly undemocratic establishment and that is constantly being used as an excuse to continue with the current system.
It's really an unresolved question at the moment.