I think its a huge gray area Snowden walked into and while he could have handled things better I suspect operational constraints have more to do with the flaws in his plan than an actual desire to disclaim ownership.
I'm pretty sure Snowden believed the NSA [among others] would catch onto him very quickly and he had to dump everything to keep it from falling into "hostile" hands as soon as practical. Given that, I think he made the only practical choice he could but he isn't a "good" guy in the sense of a hero. More of just a guy who made mistakes, like anyone else.
The hero/villain dichotomy is very...cliche. Good and evil are really points of view that depend on your perception of reality and the position you occupy within the framework of a global society. The reality is the US Government is as much a villain as Snowden is. At which point, is it really fair to call Snowden a villain as the weaker party?
To most of the world, Snowden was a clear "good" as its brought the spying of the US into the light where Governments no longer have to react privately [ I'm pretty sure every Government that claimed ignorance had some clue of the capability, they have spies too after all ] but can take proper public steps to counteract the US's capabilities.
From a US nationalistic perspective, Snowden harmed the national prestige and possibly tipped off what few adversaries the US has that were too small to have the capability to accurately estimate the US's capabilities. And no, that isn't a group like ISIS. I'm talking small groups. I'm pretty sure ISIS has a good estimate on the practical capabilities of US intelligence pre-Snowden.
But honestly, the US public [the tech illiterate ones who were oblivious to what was going on] needed to be aware of it to make an informed decision to consent to it. Sadly, the outcome is they care more about the illusion of perfect security, bread & circuses than they do being informed citizens.
http://www.usnews.com/news/articles/2015/04/21/edward-snowde...
The part of all this I honestly find frightening is this:
The reality is the majority of the US population holds a negative opinion of Snowden. I find it frightening that the majority of the country happily makes an opinion formed entirely on propaganda. The reality is the US's security forces are the greatest to its citizenry. The fact the general population blindly takes their side is...disturbing on a level I can't really express.
http://www.cato.org/blog/youre-eight-times-more-likely-be-ki...
http://www.theguardian.com/us-news/2015/mar/04/police-killed...