Regarding juan27's article, I personally I don't find 20+ shot rallies to be entertaining at all, especially if the shots are high loopy ones for the most part. Winners are what make tennis fun to watch. Although not the kind where the ball just sits up and a player has an eternity to take a swing at the ball. It takes far more skill for a player to take the ball on the rise and hit a winner with minimal set up time. Endurance and speed is part of the game, but it's the shot-making that defines it.
I agree with roger that with more faster courts other player will have much many chances to defeat the top-4 than now and it`s true , but the ATP wants protect the top-4 for money and not change the courts speed , the tennis needs more variety slow courts and fast courts.
if ths continues , the tennis will be more and more deffensive in the future and with very long rallys losing the technique , quality and agressive