I think in answering that question it is important to keep in mind that even though there are significant problems related to burden sharing, not everyone is going to do what we or other people may want them to. A NATO operation versus a UN operation or operations, which could be ad hoc in other parts of the world, do have an enormous number of benefits in terms of standardization, interoperability, and these kinds of things, that simply aren't matched anywhere else.
On May 17th, 2012. See this statement in context.