Its an interesting topic. The first pitch is such a crucial aspect of an at-bat, often determining who has the advantage for the rest of the at-bat.
Alot of batters like to take the first pitch to get "settled in", expecially the first at bat of the game. I think Buehrle has taken advantage of this fact through his career; however at this point the gig is up, EVERYONE knows buehrle pipes the first pitch. In order to have success moving on he will need to adapt and keep the batter guessing, especially on the first pitch.