His grip allows him, like Agassi, to play closer to the baseline than most and take the ball early. But his hand and forearm rotation and open stance allow him, according to Yandell, to generate spin averaging 2,500 total revolutions per minute on his forehand versus 1,800 rpms for the likes of Agassi and the now- retired Sampras when they were filmed.
Yeah, that's the crux of JY's thesis on the Federer FH. If you could smack a ball like Agassi and create spin rates of a clay court player, your FH will own everybody else's FH regardless of raw power or whatever. Because with this magical FH, you can hit any angle from any height with any pace you want. Essentially, you turn the FH side of your game into a form of extended net approach. Moreover, because everybody else is using more extreme grips, there will always be holes in their strike zone that you can take advantage of.