It would seem to me that the need for reform is clear. Make the voting more like the IMF and the Security Council will gain credibility overnight.
People talk a lot about reforming the Security Council, but any such reform has to go through the UN General Assembly, and developing countries, whcih make up most of the numbers, would never vote for such disenfrancisement. They--and non-veto-wielding developed countries--already seethe at the Permanent Five, but when they thak their two-year stints on the Security Council their votes do carry real weight, as the pressures put on Angola, Guinea, Cameroon, Mexico, Chile and Pakistan made clear. No one like the status quo, but there is a profound institutional dyaminc that makes it better than most proposed alternatives.
Developing countries, in addition, don't like the voting systems of the Bretton Woods Institutions--their structures are another post-Second World War settlement, which the vast majority of countries fell into afterwards. The General Assemby may be powerless, but its existence maintains the pretense of the soverign equality of states--a notion dear to the hearts of all independent, self-governing territories. The IMF's voting system nakedly recognises established economic power, and while that may occasionall deliver outcomes developinc counties like (like the recent IMF loan to Argentina, a bad idea pushed through by G-7 pressure) these institutions are not seen by may people as being representative--the system is one reason why some claim that globalisation does not work for the poor.
Any proposal for reforming the United Nations system of voting has to take these and other pressures into account. There are arguements that both France and Britain should not be Security Council members as their power has waned in the postwar era; both countries, as well as Russia, know that Veto power gives them a legitimce thay would not otherwise have. Admit Japan (a country that constitutionally cannot go to offensive war) and you have to admit Germany. Admitting India, which has a good claim on the sheer size of its population, would antagonise Pakistan, whose only claim is its possession of nuclear weapons. The African countries would also want an input, and would you pick large but barely stable Nigeria over South Africa? Which Middle Eastern non-democracy gets the nod? In the Americas choosing Brazil would upset Argentina and possibly Mexico.
Reform of the Security Council, and of United Nations voting in general, has been discussed for decades, and the issues involved have proved so difficult that they have never been formally put forward. Operation Iraqi Freedom has changed may things in geopolitics, but it is doubtful that it could force institutional change on the East River.