Believe me I know how you feel. I also found the whole Cas and family portion of the SPN storyline to be ridiculous. Castiel doesn't even care about Sam, he only cares about Dean. Yet Sam is supposed to risk his life and die for Castiel but Cas in turn neglects him and treats him so horribly. Castiel and Sam don't even have a relationship, Castiel never comes to Sam when he calls for him, Cas wanted to leave Sam's soul in hell and he didn't give a damn if he hurt him by bringing his wall down. So how much does Castiel really care for Sam? I would say minimally at best. Cas is all about Dean.

When did Cas become family? When did this happen? Just because Castiel saved them a bunch of times, when did their friendship become family. I just don't buy it. Maybe it's because I don't see Castiel as a human being or maybe it's just because I just don't see him as a fully fleshed out character but I find it all to be a little too much in terms of what is believable.

I agree, I think the entire show is quite Dean-centric and I think the show can only get better by having Cas leave.