Yes, at first journalists from reputable publications guided the redaction process. However, Wikileaks also gave access to unredacted documents to some very dodgy people, including Israel Shamir, who may have shared documents with the Belarusian dictatorship, leading to arrests of activists (c.f. http://www.guardian.co.uk/media/2011/sep/02/why-i-had-to-lea...)
Of course the unredacted documents were ultimately released. This was done, as I understand it, by a combination of a Guardian journalist revealing the password to a file that he thought was not public and WikiLeaks putting that same file on a server.
To quote from The Guardian: >>The newly published archive contains more than 1,000 cables identifying individual activists; several thousand labelled with a tag used by the US to mark sources it believes could be placed in danger; and more than 150 specifically mentioning whistleblowers. http://www.guardian.co.uk/media/2011/sep/02/julian-assange-a...
I'm not suggesting that The New York Times or The Guardian are perfect - they aren't - but they have decades of experience balancing the costs and benefits of leaks and overall they do a good job (from the Pentagon Papers to today's report). By comparison, what have we learned from the leaks of the diplomatic cables that was worth people getting arrested by dictatorial regimes or getting killed?