Freida don't care
Piek don't care
Nothing all that interesting has happened to any of them so they're mostly just middle of the road characters.
Mikasa only gets a 4 because of the Ackerman mind control thing. It makes her slightly more interesting but she's still mostly irrelevant.
Historia lost a point because she's stuck in a chair during what's possibly the most important arc of the manga. She'll gain it back and then some if she takes the splotlight again the way she did in Uprising.
Annie being in stasis definitely helped her stay on top. She was pretty interesting when she had the spotlight and I wanted to see more from her.