First, I feel that Snowden should actually have his day in court and present his case before anything related to a pardon or commutation is discussed. The American people need to see and hear both his and the government's position and evidence in a more balanced, less sensational environment than the MSM gives us.
Second, I feel that neither Manning nor General Cartwright should have their sentences commuted. They were both members of the US military who had sworn oaths regarding their behavior and ethics in their service and disregarded them. Gen Cartwright, as an officer should be held to an even higher standard. They were both tried, found guilty and sentenced. What message does it send to the rest of the military if they don't have to serve their sentences? Why should anyone in the military feel compelled to obey any order or protect any secret if they know that whatever punishment they get will be commuted and all they need is some publicity to make it happen.