Nixon wasn't voted out. He had the courtesy -- and the courage -- to resign before a vote ever took place.
Of course, Nixon did not have a friendly Senate (or House). And the press was on his case 24/7, 365.
Obviously, Obama does not face the opposition Nixon did. Nor does he have the courtesy...or the courage.
You are dead on, though: Nixon committed far fewer breaches than has Obama.
Yeah, I know. After I typed it I realized I meant to type "driven out". He resigned after some of the Congressmen told him that he would definitely lose the vote. I agree with the rest of your post, in particular that his worst transgressions were minor compared with Obama's normal conduct.