I think you are going a bit overboard to say that W was one of the most liked Presidents ever. If you recall, at the end of his term, his numbers were dismal and he probably couldn't have been elected dog catcher. And that is the reason Obama was elected the first time - because people didn't more of the same - they voted for hope and change. Now Obama's numbers are down. Bill Clinton's numbers were dismal at the end of his Presidency, and poor Bush 41. If the election had been held a year earlier, he would have had a 2nd term. But the economy turned, people forgot about the first Gulf War and he was voted out of office. Just about anyone who becomes President ends on a down note. Things happen or don't happen and they let us down.
I think more people admire "W" for his behavior out of office than they ever admired him in office (except right after 9/11)