My impression is that Assange has become the bad guy because he potentially torpedoed the presidential aspirations of HRC. Prior to that publication, unless you were the target of a leak, what Wikileaks was doing was in the obvious benefit of the people. As the bad guy, it becomes much easier to infer malicious motives.

That said, Wikileaks was very proud of its "reporting" track record, methods, and sources. Their minimal exposition was journalistic cover for their original sources that was typically so thin that it would be difficult to contain errors.

Based on that track record and lengths Assange has gone through to maintain that integrity, I tend to believe who he says his source wasn't, that he would not intentionally reveal a source - living or dead, and that their are likely intermediaries or collaborators that would be compromised even if the original source would no longer be affected. That chain of trust is how they help ensure other leakers come to them first, and it seems their opsec is good enough to keep those sources secret even when the organization is significantly compromised.

I completely agree that they often oversold their releases. There were often claims of a deadman switch as well. If that hasn't triggered after all that's happened, was it a bluff? did it fail? was it compromised? did it contain information about the wrong target?