You know the saying beggars can't be choosers? We are currently begging for transparency.
The filtering process by independent journalists is the only actual recourse I can think of to solve this. Exfiltrating confidential documents is usually not a process that gives you a lot of time to sort out what is worth it or not, furthermore the volume of data might very well also be a problem to handle on your own.
Consider the time it took a lot of journalists to find the pertinent documents in this specific case among about 200,000 leaked documents (of various lengths), when Snowden is thought to have exfiltrated 1.7 millions documents.