The UN appears to get getting tired of peacekeeping missions that drag on. Now there is more talk at the UN in favor of "Peace Enforcement" operations. For example, when the UN finally decided to do the "Peace Enforcement" thing in Sierra Leone, the whole business was cleared up in a couple of weeks. Such strong arm tactics are also working in Congo, where peacekeepers have been turned loose on militias that have long opposed settling down.
The UN has long been reluctant to engage in peace making, partly for philosophical and PR reasons, and partly for practical ones. The sad fact is that few countries have troops capable of the professionally executed operations required for peace making. To shut down troublemakers, you have to move fast, otherwise you get bogged down in low level violence that favors the irregulars. Everyone knows that a few thousand American, British or French troops could go into these areas and shut down the armed gangs that pass for "armies" in these crises areas. That's what happened in Sierra Leone (where British troops did the work.) These troops have the advantage of training, leadership, and rapid transportation (high tech armored vehicles or helicopters and other aircraft.) There are also second rank forces, like Bangladesh and Pakistan, which will go in on foot and clean out all but the most hard core warlord forces.
But nations with competent troops, are not keen on sending a lot of them off to work for the UN. Pakistan and Bangladesh have contributed 17,000 troops to UN peacekeeping efforts, and are unable to provide many more. The Western nations note that whenever they send troops to these peacekeeping missions, the troops are often stuck on the job for years and years (like the Balkans).
The UN is trying to work out a deal whereby the first rate troops go in and shut down the warlords, followed by less capable forces to do the usual peacekeeping. While there is a lot of international support for this, the few nations possessing the "shock troops," are not as enthusiastic. They don't trust the UN to use their highly trained troops in a responsible manner. The UN leadership has long been known for its corruption and incompetence, and that is not expected to change anytime soon.