Yes, we can't judge a character until dozens and dozens of episodes have aired. Like what Iris got, right?
If you want to be in denial of patterns, be my guest, but it's not my fault. Every female character before her who didn't get a stated goal right away (Misty, Iris) didn't get as much development by their ends as those who did (May, Dawn), and I'm sorry but whether you like it or not, every character only gets one chance at a first impression and this is what Serena's was: an aimless satellite who falls into damsel-in-distress uselessness almost instantly.
Oh, and let's see if she ends up needing him to go rescue Fennekin next week in the Furfrou episode, too.