First, defensive medicine is real. Every doctor knows it. Although the number is difficult to quantify, Price Waterhouse did so in their 2008 study that estimated defensive medicine costs $210 billion a year. A Congressional Budget Office study from December 2008 backs up that number.
Although this study is touted as verifying that defensive medicine is not a significant factor in healthcare costs because tort reform will only reduce costs by 0.5%, the fine print showed that number to be based on insurance premium reductions. It added that when defensive medicine is figured in, the total percentage could be as high as 7%. When multiplied by the $2.4 trillion in overall healthcare costs, that comes to $168 billion per year. Even in the healthcare world this is not an insignificant number.
Second, the current system doesn't give real justice for patients who have been truly harmed in medical malpractice. It takes years for a lawsuit to garner any money for patients. Much of the settlement/judgment goes to the plaintiff's attorney. Plus, it's rare that there will be a change in the physician's medical practice. There's no current mechanism to have the lessons learned from this trial be carried out for the specialty as a whole.