@Cynic doesn't seem like that to me.
His character development setup is pretty clear, everyone else is fighting for a reason, he doesn't have one.
What's more, he has completely resigned himself to being inferior to Noda.
Even if he doesn't change that much, he draws contrast between himself and the others in Seio and presents more clearly their desires and the hurdle they have to overcome to reach them.
I guess that makes him annoying as he is also dismissive of Bungo's enthusiasm but he has a purpose at least