Snowden's revelations about the NSA spying on American Citizens should earn him immunity from prosecution as a whistleblower. That was a valuable and risky thing he did.
However, his revelations about NSA spying outside the USA have caused severe and lasting damage to the USA's reputation, and to the USA's ability to collect intelligence that it needs to defend it's interests, **including national security interests**. That was a dangerous and over-the-top thing he did -- it **is** treason, and the severity of that (IMHO) outweighs any potential immunity he might have deserved from the above.
Snowden dropped a tactical nuke when he could have used a stick of dynamite. This indicates to me that his goal was to bury the NSA, not to reform it. In my opinion, this moves him from hero to traitor, and he needs to answer for this.
I think he is relatively safe if he stays in Russia. "Relatively". Should he leave there, he should prepare to be dragged into a van with a canvas sack over his head -- the subject of an "extraordinary rendition." (This is of course illegal. I don't condone it, but I do expect it.) He's barely safe in Russia, and probably not safe anywhere else. He made his own bed, now he gets to sleep in it.
I fully expect this post to get down-moderated into oblivion.