Wikileaks is far more than just that.
They leak all manner of documents, the Iraq war was just a tiny amount of it. They leaks cables and other communications between embassies, individuals and organisations. I read an interesting leak about China's nuclear advancement that they're keeping heavily under wraps. Interesting stuff.
So yeah the war is just one part of it, but Wikileaks are exposing governments worldwide and showing just what little tinkers they are. This is why Assange has been hunted down and large companies has been stopped from dealing with them; PayPal, Amazon, Visa and more were used by Wikileaks (for hosting and accepting donations, mainly) but they've (obviously because of government pressure) stopped, to certain extents, dealing with them.
It's basically the biggest mass-exposure of worldwide corruption and other secret things that the government would rather you didn't know.