Good question. At first yes... now a rather woolly no.
Some of the information coming out of the cables (and all of the information is only the subjective point of view of American diplomats, remember - not gospel truth any more than anything you read in a newspaper is. It is, however, very likely to be true).
I directly know people who have been imprisoned by a terrible regime as a result of being name-dropped in leaked cables. Good, innocent people who spoke to American diplomats in confidence and never expected their words to be broadcast around the world, and to be read by the repressive regime they live under.
Undoubtedly people have already died as a direct result of Wikileaks.
Assange and his people have been careless in how they have done this, and we have to look at human consequences like those I mentioned and wonder if it is worth it, for the 'greater good'.