The Watson show was a not a completely fair match-up since Watson had a much better average buzzer time than his human opponents.
If this was not the case, I would speculate a really good human opponent could beat Watson at least some of the time.
On the other hand, nobody would dispute that a machine has faster reactions than a human, so maybe that makes it less interesting. Tough to figure out a great way to resolve that.
What is fair? Defining fair in terms of equal outcome is vacuous here.
For a bit I thought it would be more interesting to let the humans ring in as soon as they had read the question, but the problem is that today they would slaughter Watson, and three years from now Watson would slaughter them, and possibly without even updating its software.
I suppose the most fair thing to do would be to do away with the buzzer entirely. Let all players choose whether or not to answer all questions (that is, all three could get it right, all could get it wrong, one right, one abstain, one wrong, etc), and check the scores at the end. Without the buzzer advantage for Watson I suspect Jennings and Rutter still win... for another year or two, anyhow.
It is interesting to watch machines encroach on things we once considered exclusively human mental abilities. In the early days processors just multiplied large numbers faster than we could. Then they beat a grandmaster at chess and now a machine is definitely better at Jeopardy.
Allow both contenders to press the button within the first 2 seconds and, if they both buzz in within the 2 second window, the human answers first, because Watson could be trusted to "lock-in" it's answer.
Points are issued to whomever gets the answer right, allowing for both to receive or lose points on the same question.
I'm not really sure if Watson's model goes as far to consider other players' Daily Double behavior, or simply examines other players' scores. It would make sense to try and look at the game theory aspect though, especially in an iterative-game scenario. If a player bets hyper-aggressively on Daily Doubles (and Final Jeopardy) and gets most of them right, you'd think Watson would want to take that into consideration.