In my opinion, the Yankees need to sign more Japanese & South Korean hitters. Japanese & Korean baseball players are generally more fluid and exciting. They also are usually about contact and making base hits - which is something the Yankees don't seem to how know to do (at least in the playoffs). Getting Munetaka Murakami would be a good start (when he's ready).
Hideki Matsui is a huge reason why the Yankees won the 2009 World Series. He was the WS MVP but just in general, he was a CLUTCH hitter and got base hits. Matsui could suit up right now and get more hits than IKF, Donaldson & Carpenter combined. He threw out the first pitch at Game 3 yesterday.