"This is shaping up to be a Wikileaks, or even Snowden-level, revelation."
In raw data it's already 10 times larger than Wikileaks - and the interesting revelation that there are scanned paper docs dating back more than 40 years will have a lot of people looking over their shoulders.
As with Wikileaks, the releases are being curated and dripfed to keep up interest. I'm pretty sure there will be a bunch of attacks aimed at grabbing and releasing the enture dataset.