Have your say! Which rule would you change?

If you were in charge of tennis for the day and could make one radical change to the laws of the game, what would it be? Lengthen the games and shorten the sets (or the number of sets)? Make a let a second, not a first serve – or even outlaw second serves altogether? The “No advantage” rule or the match tie-break like in doubles? You can change one thing and one thing alone, so use your change wisely… And remember, it’s a change to the rules, so let’s leave the calendar debate for another day. Have your say! In answer to many of the comments below, Hawkeye technology is not necessary here at the French since the ball leaves a mark in the clay dust which the umpire can check afterwards.