Where else are we going to get insight into the globbal power "underworld", which the intelligence community just happens to always have a finger in? Anonymous sources feeding into New York Times? Because that's all we had before and continue to have today otherwise.
People just don't like when certain inconvenient information comes out and Wikileaks didnt care about the source.
People constantly try to pin ideological stuff on Wikileaks or data leaking in general but that misses the bigger point and it's a point that extends beyond Wikileaks itself and goes into information releasing in general (we don't need to defend Assange personally or Wikileaks itself to be concerned or defend the general idea). I also highly doubt they are selectively choosing NOT to release political information... like news outlets apparently do.
But I also don't care, there's a huge amount of risk and blowback doing such a mission regardless of source or content which we should respect.
They get what they can from where ever and publish it if it has some value to the general public, and we've gotten tons of value from Wikileaks already. So do plenty of other organizations now inspired by Wikileaks, plenty which have exposed corruption in a new way (like Panamaleaks).
The fact this sometimes can have an 'agenda' or be exploited by the original sources will never negate the value of a neutral 3rd party who releases stuff publicly we'd never see otherwise. And will continue to do so as long as operational.
My only fear is that there won't be people brave enough to do this given nation-state harassment and those who think its all a political-inspired conspiracy (which litter every social media site).