The fact that modern democracies have these grey-shaded institutions and make use of them to spy on each other is something that we probably will have to live with, and maybe even appreciate. As long as the targets for the espionage is large centralized power centres, like government, the military or organized, violent groups. In some way I think that we need, as in Iain Banks culrure-books, someone to step in in "special circumstances." Assassination, revolt or similar should of course rather NOT be the job of our intelligence services. Think if MI6 and CIA hadn't instigated a coup in Iran in 1953 against one of the regions first democratic government? How would the middle east have looked today?
But the really big wrong that Snowden has revealed is mass-surveillance of the entire population. This kind of technological spying can only be used for one thing: anti-democratic, cost-heavy practises, targeted against the press, grass-root and the very population that the system was intended to protect.