The IMF really serves its best role in relation to underdeveloped and developing nations. The IMF is just not capable of managing all of Europe. The IMF works well as a large International organization working with nations where money goes a long way. The IMF specializes in loans to impoverished nations around the globe. The EMF would specialize in Europe and therefore be able to take on debt laden nations like Greece and enable them to rebuild their economies. An EMF is a necessary organization for EU success.
Because the EU is a self-contained set of governments with its own intricate economy, it's important to establish a monetary fund that is tailored to the needs of that group, and kept separate from an international monetary fund. The legislative checks and balances of the EU could help them ensure that their monetary fund remains stable, even if the rest of the world is in recession.