This latest leak reduces the NSA's effectiveness at whatever they are doing. That is a good thing if, and only if, the NSA does more harm than good.

It tells us nothing about whether the NSA does more harm than good. That is the key point that distinguishes this leak from previous leaks. This leak does more to reduce the NSA's effectiveness than to improve the quality of public debate about NSA policy.

(Previous Snowden leaks make me suspect that the NSA does do more harm than good... but I can disagree with Kevin's conclusion and still respect his position.)