I love Robyn. She's been really refreshing so far - a guest character with an actual personality, who seems like a real person! I find her obvious Kalinda hero worship kind of cute and fitting with her (presumed) age of 24-25. That bit at the motel where she was rearranging the flyers was a nice little character thing to do. Far and away the best new character they've had this season, all the other ones -- Maddie, TR Knight, Kristeva, Amanda Peet -- have seemed shallow and one-dimensional to me. (And I'm guessing Kalinda likes her, or at least doesn't mind her, since she didn't so much as glare when Robyn answered her cell phone for her.)
The thing you have to remember about Kalinda is that she has deep respect for work, and for someone who is good at his or her job. That respect trumps everything else, even a knee-jerk dislike or disdain that she might form on first impression. That, after all, is why she initially was attracted to Alicia. At the beginning of the pilot, Kalinda judged Alicia quickly and harshly, clearly with no plans to like her. By the end, she was impressed with the clever way Alicia won her first case. The mutual respect that Alicia and Kalinda had for each other professionally fueled their friendship, and I think Kalinda has the same sort of despite-herself respect for Robyn: the fact that Robyn is smart and competent makes all the difference in the world to Kalinda.
As far as the development of the character goes,, I think it's pretty clear that Robyn is an actual character that we'll be seeing next season, whereas Maddie, Jordan, and Laura are all (I believe) one-off plot devices. That's why we're seeing more depth to her. I agree that she's a good addition to the mix, and I like seeing her work with Kalinda. Good visual contrast physically, and good character contrast in general.