looks a bit more dodgy thesedays doesnt it
i think its his crappier movement - he's not in as good a position as the last few years and his opponents are really abusing it more and more
spot on. i would just add that a 1 hander just has to be too precise. too many variable to account for and accordingly, less reliable than a 2 hander.
his greatest limitation off that wing is that he cannot really attack or finish the point. quite often he is forced to just get the ball back. on clay, he is being asked to hit that backhand repeatedly and its simply too difficult a stroke to hold up on sustained basis.
as you have suggested, his ridiculous movement gave him the time before to execute his options but now that movement is on the decline and it shows at the pump.