With the benefit of hindsight, I think Bush was correct in choosing to take the war to the enemy but wrong in believing that Saddam was more dangerous than Osama. I believe psychologists will conclude that Bush Jr. had a personal type problem with daddy's decision not to press on to Baghdad in 1991, but that history will judge daddy's choice was wise.
I think Bush Jr's most tragic weakness was his dogmatic type of thinking. I know it's a popular belief that Bush wanted to "finish what his daddy started". Maybe there's some truth to that - but there's a far more important issue - after 9/11, we attacked the wrong country that began with the letters "IRA..." My biggest criticism on Bush is that while we're fighting over there instead of here, he didn't do ENOUGH.
Saddam and Osama were both dangerous, just on different scales. Hussein's fate was certainly just.