It's hard to justify any of the un budget. All of its committees and bureaucracies seem compromised, if not outright corrupt. I'll keep my money at home, where there's at least a minimal chance of accountability.
Let it not be forgotten that some of the finest wires of the Cold War came down to the delays in international diplomatic communications between Washington DC and Moscow due to the need to relay messages via embassies.
People have gotten so used to an international power structure with high speed communications and well defined diplomatic channels that they mistake the purpose of these organizations for their effectiveness. The alternative is a lot worse.
It was also the League of Nations failing to live up to it's principles when Japan invaded Manchuria.
The UN was a dream to try and resolve things in a multi-laterial world, and sometimes early on was effective (See Korea). after the debacle of the Korean War (Moscow boycotting rather then using their veto), the progress in the cold war was almost always bilateral. (not always though).
In it's current form, it's useful - but I think the WTO / World Bank and the Red Hotlines have been far more useful.
Isn't the only way to make UN more efficient to make nation states more efficient?