I definitely don't think that is always a positive thing but I struggle to think of anything which Assange leaked which I really disagree with. Probably some parts of cablegate should not have come out as they were very "inside baseball" talk between diplomats and were too easily construed negatively in the media, though, I think for the most part our allies realized that they said the same things about us in their private communications and there was really no major fallout from it.
Now, all that said, Assange did break the law and I don't think there should be no consequences for that but the way the US went about this (across 3 different presidencies) is just terrible. Nudging and cajoling and perhaps berating our Swedish allies to jin up a "rape" case against him so he could be extradited from the UK to Sweden and then obviously to the US, and, denying that we were doing that was just dirty on our part. I'm sure if there is a cablegate 2.0 we'd find we did some fairly terrible stuff to persuade our Swedish allies to prosecute this.
Ultimately the simple reason I think there is near positive reaction to this news is that everyone understands that even given what he did, it does not merit almost 15 years of prison in some really terrible conditions. Should he have walked away free? Maybe, maybe not but he should have had a fair trial with fair charges and faced a fair jury and he never got any of that, he was effectively extrajudicially jailed.