I have often heard, when someone is referring to the US government, that the right hand doesn't know what the left hand is doing. We are still even now, emerging from the Cold War era thinking that keeping secrets, even amongst those individuals who are thought to be on the same side, is the best way to operate. This type of thinking should no longer be enabled.
Our world has grown larger due to the advancements in communication technology and online resources, we can no longer afford to have our government agencies stand in the dark while the rest of the globe passes them by. I would recommend the adoption of a type of institutional repository of government knowledge - a place where information of all types from various agency points could be stored and accessed internally by those who needed it. This would not only include the standard explicit knowledge pieces of documents, reports, memos, etc., but also a catalog of the individuals who work within our government and the tacit knowledge (the experience and topical intelligence) that each person can bring.