It is very unlikely a single entity can control the whole system. The people around the wise king is the root of corruption. FED is not the problem, but those banks are
1) The FED is wholly owned by those corrupt banks. If you believe the banks are corrupt then so if the Fed. It is like saying that guy is a murderer but his right eye is innocent.
2) The king might not be wise. That is the entire root of the problem. Greenspan admitted he was WRONG. He thought loose money would be corrected by market forces. That banks wouldn't take on too much risk and act in their own self interest. Greenspan forgot (or was likely too close) to realize that assumes all the actors are rational and face real consequences.
So yes
if the FED was completely incorruptible, always accurate, and it could be guaranteed that would NEVER change in the future (not in a decade, not in a millennium) then monetary intervention (tightening and loosening to match money supply growth to economic growth) could in theory be beneficial.
The reality is the FED is BOTH corrupt (beholden to the banks interest over the interests of the citizens) AND fallible. We have 50 years of horrible monetary policy as their track records. On a larger context that concept is called a benevolent dictatorship.
http://en.wikipedia.org/wiki/Benevolent_dictatorship Free markets are to Democracies as Centrally Planned markets are to Dictatorships.
"Democracy is the worst form of government except for all those others that have been tried."
Maybe someday technological and evolutionary progress will allow for the creation of the perfect Utopian to administer the Utopia see "The Culture" fiction (Iain M. Banks). In the meantime Democracies and free markets are optimal given the limits of human technology and evolution.