I agree with everything you said except I think it is a little naive to believe he'll only get "more than a couple years in prison."
Here's the thing: Snowden, regardless of morals, upset a lot very powerful and influential people. These people might have calmed down a little since they were calling for him to get the death sentence, but these aren't the kind of people who won't try to get revenge if given half an opportunity.
Just look at what they did to Chelsea Manning (formerly Bradley Manning), he got 35 years(!) for leaking a bunch of embarrassing diplomatic cables where key US politicians wrote what they really thought about foreign leaders and diplomats.
Snowden upset people in the US government just as much. He essentially took a bunch of power away from them, and people in those positions shrive on power. Do you really think they won't get every pound of fat out of Snowden that they can? Because I do. 35 years if he's lucky.