When your hair takes long to dry I think that usually means that the porosity of your hair is good (it holds on to moisture well like a new sponge vs. an old sponge that dries out quickly). While it can be annoying, its not a bad thing. The porosity of your hair could have improved from a protien treatment, using a porosity control type poo/condish or something else that altered the pH of your hair. I know that there are plenty of threads on porosity here if you want more info. Maybe thats why your hair is taking longer to dry than it used to.