Originally Posted by above bored
Only continental and eastern gripped backhands, such as that used by Federer, make higher balls more challenging. Nevertheless, you can still hit a decent enough ball. Semi-western backhand grips, such as that used by Almagro and Kohlschreiber, are more comfortable for high backhands, but not so good for low balls. These principles are well established, based on the anatomical reality for all players, not just because of the Federer/Nadal match-up.
You are always going to be at an anatomical disadvantage if you are going toe to toe against another pros forehand with your backhand. Forehands are almost always stronger than backhands, regardless of the opponent, but especially in the case of Nadal, who has a forehand better than most.
I would also add though that eastern/conti bhs generally are easier to slice off of. So even though high bhs are a bigger challenge compared to semis/west grips, the player can use the slice when the ball is high.
The problem is that the natural cross court slice goes straight to nadal's fh, which he has no trouble whipping.