Competitive balance in sports is among the most commonly discussed topics among sports economists. Three of the four most cited articles at the Journal of Sports Economics, for example, directly address the topic while the fourth is also related. The discussion, however, seems to have focused primarily on team sports rather than indiviudal sports.
In his ESPN Magazine article this month, Bill Simmons essentially suggests that nowadays golf is great because Tiger dominates while tennis is awful because Federer dominates. I'm not sure whether the data actually backs up his claims (although the "Tiger" effect certainly seems to be real), but his column poses several excellent unanswered questions for sports economists: how does competitive balance affect demand for individual sports, does competitive balance affect different individual sports in different ways and if so, why is this the case, and does competitive balance affect teams sports differently than individual sports?
Let the debate and, more importantly, the research begin.