The most powerful military the world has ever known already exists; and it would not be capable of "fixing" North Korea or Libya without sustaining (and more importantly, inflicting) significant casualties. The best course of action, militarily speaking, would probably be to significantly nuke Pyongyang quickly and have S. Korea take over administration of the country. This is not politically or morally acceptable.
That's part of the problem: The moment you declare a regime as morally bankrupt, you are stating your own goals are somehow more enlightened and worthy. In some cases this works, like against the Nazis, but in most, like the Yugoslav war you cite, it's only a matter of opinion - For every Srebrenica there is a Krajina, unfortunately. The people involved in such generational hatred do not escape their own guilt, regardless of which particular side they may be on in any particular indecent. Getting involved in these quagmires often only intensifies the conflicting hatred for a later date. Even worse, who then protects us from the protectors?
Your desire is a noble one but unfortunately completely at odds with human nature.