Your rationale is at least consistently shallow. Don't go into the deeper water until you feel comfortable.
So why did Bush ask Harvie Wilkinson if he exercised. Wilkinson, I Believe is 59-- Bush's questions of him suggested that he was concerned about his nominees longevity. Does Harriet Miers look like someone who'll be around a long time-- does she look in shape or youthful?
Face it, it was a crap pick that apparently violates many of Bush's stated criteria.