If the NSA didn't guard against him using accounts with more clearance to download documents he wasn't supposed to have access to, I don't think Snowden's intelligence is what we should be worried about.
Which I don't understand... they're claiming that we should trust them but they aren't (or shouldn't be [hiring]) the most brilliant people. So, how many other holes exist in their systems and oversight that are unknown because there aren't brilliant people finding them?
Not only that, but isn't the NSA required to have a sufficient level of auditing to detect (or at least record) those accesses before the systems are even fired up?