What characteristics are most important for the next generation of doctors?

Personality testing may help determine if hard work and conscientiousness can make up for low test scores, especially of the multiple-choice variety, read: “differences in cognitive ability." Some data says it can.  That is, according to Deniz S. Ones, a professor of psychology at the University of Minnesota, "'If someone is at the 15th percentile of the cognitive test but at the 95th percentile of conscientiousness, chances are that the student is going to make it.' That student may even eventually outperform peers who have higher cognitive test scores but who are less conscientious or more neurotic and stress-prone."

Caveat: the aforementioned standardized tests, be they about personality or cognitive prowess, can be only be relevant or useful depending on the intended occupation (i.e., specialty or field of interest) and the expectations of the public.

Chen, P. "Do You Have the ‘Right Stuff’ to Be a Doctor?" Jan. 14, 2010.