Age: 57
Title: Chairman and CEO, Association of Tennis Professionals (ATP)
Pro: The irreverent Rhodes Scholar from South Africa raised prize money by 10% this year and has most tournaments starting on Sundays, instead of Mondays, to gain weekend fans. Smaller events now have a round-robin format until the final rounds, giving spectators have more chances to watch top players.
Con: Does the former Disney exec and tennis outsider know the sport well enough? Tournament directors, who have shouldered the costs for many of his ideas, tend to doubt it. De Villiers can also seem indecisive: when James Blake missed a cut in March under the new round robin rules, de Villiers put him back in the tourney before reversing his decision, causing controversy.