The girls of the series receive further exposition and development.
Continuing with the standard Monogatari formula, all of the girls continue to have problems with their respective apparitions, and Ararararagi must help them all. What makes Bakemonogatari 2 different from its first season is the narrative changes perspectives. Instead of being from Arararagi's point of view the whole time, each girl gets their time to really shine and actually tell their story. It's one of the best things that has happened to the franchise. By doing so it gives us full insight as to how the girls think and developing them further.