Ok, in Jaune's defence.

Everyone is getting more screentime and character development than Ruby. While I do agree Jaune is getting more then he needs, let's not forget the fact that volume 5 was more about Blake's, Weiss's and Yang's problems then Ruby.
Ruby is in that awkward "Goku" spot where despite the fact she's the main character, she just stays the same.

Also, the Jaune vs Cinder fight was going to happen eventually because of the whole, you know, Cinder killing Pyrrha. It just happened sooner then expected in a… underwhelming fight.
Also, let's not kid ourselfs, Cinder will come back.
We don't know when or how, but they will bring Cinder back.