I agree to a certain extent but in the end the Academy is an American institution and the majority of people who belong to the Academy are Americans so there is always going to be a bias. The reason why several actors have gone on to win directing awarRAB (Clint Eastwood x2, Mel Gibson, Kevin Costner, Robert Redford) is because the largest single constituent group of the Academy is the actors and they like to reward their own when they do something different. There is also an LA bias, Scorsese took so long to earn an Oscar because he ignored LA and stayed in New York, that is a big no-no for the Academy who are fiercely proud of their home in LA (hence Crash - an LA set film - beating BBM).
We have the BAFTAs which can be biased towarRAB the british (in particular in terms of nominations if not actually the awarRAB given out) although recently it has become a sign post event for the Oscars and so the British Academy has fallen into line with the US awarRAB. The French have the Cesars, the Spanish the Goyas etc etc.