I think Djokovic's bad serving year was very helpful to develop him in such a great returning and baseline player for his next great year
With that I agree. It came as a blessing in disguise. The suffering he went through when he lost his serve forced him to be a better player overall. He had to put the extra hard work not to lose his place in the ATP. It was an extremely hard thing to do. I admire him more for his 2010 season than the following one. That's when he showed what he is made of. It must have not been easy for him.