The biggest secret is that the CIA are utterly incompetent, although it isn't that much of a secret due to their incompetence at keeping secrets. The documents released about the agency's activities include the 'news' that the tried to assassinate Fidel Castro, this is presented by most of the media outlets as something to be ashamed of when the only regrettable aspect is that the screwed it up and screwed up every other attempt at freeing Cuba from brutal tyranny. The Washington Post repeats the myth that Castro toppled a pro American government, in fact the thuggish Batista regime was opposed by the American government who imposed an arms embargo on it and backed the democratic opposition to the regime (who have been airbrushed out of history by Castro apologists).
Other CIA idiocies include opening Jane Fonda's mail, now whilst she may have been a traitor she was hardly so subtle about that they had to resort to illegally monitoring her communications. (Incidentally isn't Barbarella a great film?).
The CIA has also confirmed their involvement in the botched Chilean coup of 1970, and despite the popular myth had bugger all to do whith the 1973 effort which was brutal, but competent.
One of the few CIA successes of the era appears to have been helping Turkey invade northern Cyprus in response to the coup d'etat that had been carried out by Greece's military dictatorship. This seems like a justified action morally as well, making it a rarity.
The general theme that emerges from the CIA's history is that they are much better to have as enemies than friends.
Arkwright's Mill, Cromford, in 1947
41 minutes ago