I just think that since his wrist injury in 2007, he has/ will have times/moments when he feels tentative in really 'hitting out' - due to natural physical and psychological reactions.
I think it is constantly in the back of his mind.
But when he's confident in it etc, it's great to see.
In my opinion, Andy is currently hitting his forehand better than ever.
I'd have thought that after four years he might just have managed to get over that, but he clearly hasn't because he often mentions his wrist problems - and I remember last year's Paris Masters (I think it was anyway) against Nalbandian when he definitely did something to his right wrist, which fortunately turned out to be nothing serious, but I won't forget the expression on his face when he clutched it and hurried off court to have it checked out. I wonder if the fact that he's hitting it harder than ever is due to the Adidas team, or has he perhaps been getting a little psychological help?