Why do you think people don't like Jo or Jo/Dean?

The writers didn't seem to a have a firm hold on their vision of Jo, so her characterization was a bit over the place. In ELAC, she comes off as this wise-ass tough chick stuck at home... but by No Exit they make her seem like a whiny hunter rookie. It just didn't go over well with the fans. That, and the fans they automatically rejected the Dean/Jo ship being forced on them. Which I agree with. An EPIC romance, one that really connects with the audience and fans, needs to be more organic. It needs to happen gradually (see Booth/Brennan or Tony/Ziva).

But the writers created this character SOLELY to be a love interest for Dean and... I think they worked the story out from there, building on her story after they decided she was a love interest, rather than letting her have more depth. So I think it was doomed to fail. Some fans outright rejected the character.

Because, It was akward to see them as a couple.
People felt that it was'nt enough, jo wasn't enough.there was just this something wrong with the couple. Oh,and the primary reason that itdid'nt work cause people felt that jo was like dean's 14 year old sister or something