I have the idea, that if a government has to have secrets, then something is wrong. And usually the public is the one's who get it in the bum, from that. Is there really any thing that needs be kept secret from other folk ? Of course, if you want to run an aggro government, then you will need secrets, but most of this stuff is cover ups of politicians doing back door deals to fill their own pockets, or poor management of the departments they run.
I have the idea that Balstrome has to have secrets, then something is wrong. For instance we want to know his ID number, his real name, his address, when he is at home, his alarm systems code, his credit card PIN and number, if he owns a gun and where he keeps it, the combination to his safe, the password on his laptop etc.
There is public info and there is classified information. For example the SA govt may not want to tell the world how many special forces personnel it has, it may not want to publish the names of the bodyguards of the president (lest the families of these people are used to blackmail these guards), it may not want to tell the world what its defence strategies are, what the exact chain of command are, which frequencies and codes/equipment the military/police/secret service use, etc etc. There are many valid reasons why governments keep secrets. I am surprised you did not consider this.
Much of that Afghanistan stuff published is operational stuff. So revealing that stuff to the enemy such as the names of commanders or intelligence officers or liaison officers can give the Taliban vital clues on how to fight the Americans (NATO). They could for example go after a particular officer and then cripple the US in a particular sector for a long time. Same with the names of informants - not only are they and their families being betrayed, but in the future fewer people will want to co-operate with NATO or Afghani government against the Taliban and more NATO soldiers and aid workers will end up getting killed.
Even releasing videos of civilians being killed by NATO can be dangerous. The material could be used a propaganda and taken out of context - it could be used to recruit more fighters and suicide bombers for the Taliban. Secondly fake information could be slipped in with 'genuine' reports. Would Assange know what is real or not? Hell no.
In short this is dangerous. I'm all for releasing hidden deal information when it is in public interest to do so, but when it can cost lives, I would not be so happy. Perhaps if Wikileaks was around in 1944 they could have published the details of the D-DAY Landings too.