There are apparently around 500,000 people who have access to the hoards of data that the US National Security Agency (NSA) is collecting about you and I. Only one of those people was Edward Snowden, and without anyone noticing he managed to extract up to 200,000 documents from their systems and leaked them to the press, and is now a political refugee. This really begs the question that if the NSA can't keep its own "Top Secret" classified files safe from leaking out, how can any intelligence agency protect your metadata from the exact same thing?
This specific issue of the leaking of metadata hasn't really garnered much attention in the media. It generally gets covered when one calls into question an intelligence agency's ability to keep the data safe, however the discussion normally focuses on external attacks like the ones that happened to Sony, Target, or Adobe, or a state-sponsored attack. Lets get real though, whilst there's no such thing as perfect security, it's unlikely that the NSA is going to fall victim to an external attack, as generally these are a result of technical incompetence by the people implementing the systems. The NSA is employing the smartest and brightest people in the world and is very well equipped to deal with threats like these. What intelligence agencies are not well equipped to deal with though is leakers, as the only way to protect data from leakers is to deny access to it - what point is there in collecting it if no-one can access it?
Shortly after the leaks started coming out, the NSA really started cracking down on system administrators, which is the position that Edward Snowden held at NSA contractor Booz Allen Hamilton. This is unlikely to be of any significant benefit, as system administrators are required to have the keys to the kingdom if you will, and they're able to access the complete set of data because this access is required to be able to to perform their job. Disallowing them access to this data would be akin to telling your car mechanic that under no circumstances are they to touch the engine.
A reason that the vulnerability of metadata to leaking is not being covered very much I believe is that the people deciding on the majority of the talking points in regards to criticism of the NSA are people and organisations very closely tied to Edward Snowden. It would seem almost hypocritical for Snowden's most ardent supporters to argue that "leaking this information could be catastrophic" whilst continuing to release more and more information derived from leaks. Whilst there is clearly a huge contrast between leaks exposing a worldwide network of rogue intelligence agencies, and leaking of personal metadata of innocent people, it's still cause to tread lightly in a world of sound bytes and only surface level analysis of significant issues by the mainstream media.
System administrators must have access to your metadata to do their job. So, the question is, is there another Edward Snowden out there willing to go a (large) step further. Is there one out there who, after seeing no political drive from the major parties around the world, is willing to leak the websites you've visited, the people you've emailed, the phone calls you've made, the transaction history of your credit card, etc etc? I don't want to find out.