First point: Obama's promised investigation into all things Gitmo hasn't happened yet. It probably never will, but I'm willing to keep hoping a little longer. And if it ever does, Cheney will be the first against the wall.
Second point: The evidence is never going to support a treason conviction for Cheney. He hasn't levied war against the United States, or intentionally supported a wartime enemy of ours. What Obama can do, and should do, is make sure he gets tried for torture and crimes against humanity, charges that are a slam-dunk since Cheney has essentially admitted to them publicly. Cheney gets his prison cell, and Obama gets to show the world that America really can police itself.
Third point: No matter what Obama does, the press will be perfectly happy to give Cheney all the time he needs to air his grievances. He is, after all, a former Vice President, and
the American press loves former Vice Presidents. I'll agree that there's no need for Obama to respond to every criticism, but when Cheney pipes up it's like shooting fish in a barrel. If people are going to hear him regardless of the response from the White House, I don't especially mind getting to hear Obama's press team slap him around a bit.
If you think the waiters are rude, you should see the manager.