This isn't that unpopular. Not that people don't like Jade, but I'm pretty sure a lot of people will agree that Jade didn't get nearly as much screen time with which to explore and develop her character as her peers did, and thusly comes off as flat and extraneous in comparison.
I don't know for sure if this is unpopular because barely any people bring it up, but I find it really weird how there are no typos in Pesterchum. The thirteen year olds spell every word -- even if it's complicated, 100% correctly. Besides Roxy, of course.