Is it just me or was his backhand beastly in the 2006 Wimbledon final? Much flatter and more penetrating than it is now.
Was it better at any other point in his career so far?
(fixed your link)
His backhand, apart from some sublime passing shots on the run, has really become worse, especially in 2010. He nets so many BHs in neutral rallies it's ridiculous and the lengths he goes to protect that wing... well you only need to see how often he runs around to hit a FH these days.
His BH at his best was in 2008 early 2009, that is the time he had zero weaknesses on his groundstrokes.